diff --git a/meshuser.js b/meshuser.js
index d365164e..afcc566c 100644
--- a/meshuser.js
+++ b/meshuser.js
@@ -1514,11 +1514,11 @@ module.exports.CreateMeshUser = function (parent, db, ws, req, args, domain, use
                         db.Set(ugrp);
                         if (db.changeStream == false) { parent.userGroups[ugrpid] = ugrp; }
 
-                        // Event the device group creation
+                        // Event the user group creation
                         var event = { etype: 'ugrp', userid: user._id, username: user.name, ugrpid: ugrpid, name: ugrp.name, desc: ugrp.desc, action: 'createusergroup', links: ugrp.links, msgid: 69, msgArgv: [ugrp.name], msg: 'User group created: ' + ugrp.name, ugrpdomain: domain.id };
                         parent.parent.DispatchEvent(['*', ugrpid, user._id], obj, event); // Even if DB change stream is active, this event must be acted upon.
 
-                        // Event any pending events, these must be sent out after the group creation event is displatched.
+                        // Event any pending events, these must be sent out after the group creation event is dispatched.
                         for (var i in pendingDispatchEvents) { var ev = pendingDispatchEvents[i]; parent.parent.DispatchEvent(ev[0], ev[1], ev[2]); }
 
                         // Log in the auth log
@@ -1561,6 +1561,13 @@ module.exports.CreateMeshUser = function (parent, db, ws, req, args, domain, use
                         }
                         var group = groups[0];
 
+                        // If this user group is an externally managed user group, it can't be deleted unless there are no users in it.
+                        if (group.membershipType != null) {
+                            var userCount = 0;
+                            if (group.links != null) { for (var i in group.links) { if (i.startsWith('user/')) { userCount++; } } }
+                            if (userCount > 0) return;
+                        }
+
                         // Unlink any user and meshes that have a link to this group
                         if (group.links) {
                             for (var i in group.links) {
@@ -1621,7 +1628,8 @@ module.exports.CreateMeshUser = function (parent, db, ws, req, args, domain, use
                     change = '';
                     var group = parent.userGroups[command.ugrpid];
                     if (group != null) {
-                        if ((common.validateString(command.name, 1, 64) == true) && (command.name != group.name)) { change = 'User group name changed from "' + group.name + '" to "' + command.name + '"'; group.name = command.name; }
+                        // If this user group is an externally managed user group, the name of the user group can't be edited
+                        if ((group.membershipType == null) && (common.validateString(command.name, 1, 64) == true) && (command.name != group.name)) { change = 'User group name changed from "' + group.name + '" to "' + command.name + '"'; group.name = command.name; }
                         if ((common.validateString(command.desc, 0, 1024) == true) && (command.desc != group.desc)) { if (change != '') change += ' and description changed'; else change += 'User group "' + group.name + '" description changed'; group.desc = command.desc; }
                         if ((typeof command.consent == 'number') && (command.consent != group.consent)) { if (change != '') change += ' and consent changed'; else change += 'User group "' + group.name + '" consent changed'; group.consent = command.consent; }
 
@@ -5770,6 +5778,9 @@ module.exports.CreateMeshUser = function (parent, db, ws, req, args, domain, use
         // Get the user group
         var group = parent.userGroups[command.ugrpid];
         if (group != null) {
+            // If this user group is an externally managed user group, we can't add users to it.
+            if ((group != null) && (group.membershipType != null)) return;
+
             if (group.links == null) { group.links = {}; }
 
             var unknownUsers = [], addedCount = 0, failCount = 0, knownUsers = [];
@@ -5779,7 +5790,7 @@ module.exports.CreateMeshUser = function (parent, db, ws, req, args, domain, use
                 var chguser = parent.users[chguserid];
                 if (chguser == null) { chguserid = 'user/' + addUserDomain.id + '/' + command.usernames[i]; chguser = parent.users[chguserid]; }
                 if (chguser != null) {
-                    // Add mesh to user
+                    // Add usr group to user
                     if (chguser.links == null) { chguser.links = {}; }
                     chguser.links[group._id] = { rights: 1 };
                     db.SetUser(chguser);
@@ -6235,6 +6246,12 @@ module.exports.CreateMeshUser = function (parent, db, ws, req, args, domain, use
 
         var chguser = parent.users[command.userid];
         if (chguser != null) {
+            // Get the user group
+            var group = parent.userGroups[command.ugrpid];
+
+            // If this user group is an externally managed user group, we can't remove a user from it.
+            if ((group != null) && (group.membershipType != null)) return;
+
             if ((chguser.links != null) && (chguser.links[command.ugrpid] != null)) {
                 delete chguser.links[command.ugrpid];
 
@@ -6248,8 +6265,6 @@ module.exports.CreateMeshUser = function (parent, db, ws, req, args, domain, use
                 parent.parent.DispatchEvent([chguser._id], obj, 'resubscribe');
             }
 
-            // Get the user group
-            var group = parent.userGroups[command.ugrpid];
             if (group != null) {
                 // Remove the user from the group
                 if ((group.links != null) && (group.links[command.userid] != null)) {
diff --git a/views/default.handlebars b/views/default.handlebars
index 734ea0c8..016b8e63 100644
--- a/views/default.handlebars
+++ b/views/default.handlebars
@@ -7539,7 +7539,7 @@
                     if (usergroups != null) {
                         var userGroupCount = 0, newUserGroup = false;
                         for (var i in usergroups) {
-                            if (usergroups[i]._id.split('/')[1] != nodeid.split('/')[1]) continue;
+                            if ((usergroups[i].membershipType != null) || (usergroups[i]._id.split('/')[1] != nodeid.split('/')[1])) continue;
                             userGroupCount++; if ((currentNode.links == null) || (currentNode.links[i] == null)) { newUserGroup = true; }
                         }
                         if ((userGroupCount > 0) && (newUserGroup)) {  x += '<a href=# onclick="return p20showAddMeshUserDialog(6)" style=cursor:pointer;margin-right:10px><img src=images/icon-addnew.png border=0 height=12 width=12> ' + "Add User Group" + '</a>'; }
@@ -12562,7 +12562,7 @@
                 if (usergroups != null) {
                     var userGroupCount = 0, newUserGroup = false;
                     for (var i in usergroups) {
-                        if (usergroups[i]._id.split('/')[1] != currentMesh._id.split('/')[1]) continue;
+                        if ((usergroups[i].membershipType != null) || (usergroups[i]._id.split('/')[1] != currentMesh._id.split('/')[1])) continue;
                         userGroupCount++;
                         if ((currentMesh.links == null) || (currentMesh.links[i] == null)) { newUserGroup = true; }
                     }
@@ -13035,7 +13035,7 @@
                 if (selected == null) {
                     var ousergroups = getOrderedList(usergroups, 'name');
                     for (var i in ousergroups) {
-                        if (currentNode._id.split('/')[1] != ousergroups[i]._id.split('/')[1]) continue;
+                        if ((ousergroups[i].membershipType != null) || (currentNode._id.split('/')[1] != ousergroups[i]._id.split('/')[1])) continue;
                         if ((currentNode.links == null) || (currentNode.links[ousergroups[i]._id] == null)) { y += '<option value=' + encodeURIComponentEx(ousergroups[i]._id) + '>' + EscapeHtml(ousergroups[i].name) + '</option>'; }
                     }
                 } else {
@@ -15151,7 +15151,7 @@
             // Add user group name
             var gname = EscapeHtml(group.name);
             if (gname.length == 0) { gname = '<i>' + "None" + '</i>'; }
-            if ((userinfo.siteadmin & 256) != 0) { gname = '<span tabindex=0 title="' + "Click here to edit the user group name" + '" onclick=p51editgroup(1) onkeyup="if (event.key == \'Enter\') p51editgroup(1)" style=cursor:pointer>' + gname + ' <img class=hoverButton src="images/link5.png" /></span>'; }
+            if ((currentUserGroup.membershipType == null) && ((userinfo.siteadmin & 256) != 0)) { gname = '<span tabindex=0 title="' + "Click here to edit the user group name" + '" onclick=p51editgroup(1) onkeyup="if (event.key == \'Enter\') p51editgroup(1)" style=cursor:pointer>' + gname + ' <img class=hoverButton src="images/link5.png" /></span>'; }
             QH('p51groupName', gname);
 
             var usercount = 0, meshcount = 0, devicecount = 0;
@@ -15172,8 +15172,11 @@
                 x += addDeviceAttribute("Domain", (d != '')?EscapeHtml(d):('<i>' + "Default" + '</i>'));
                 x += addDeviceAttribute("Group Identifier", EscapeHtml(group._id));
             }
+            if (currentUserGroup.membershipType != null) {
+                x += addDeviceAttribute("Group Type", EscapeHtml(currentUserGroup.membershipType));
+            }
             if ((userinfo.siteadmin & 256) != 0) {
-                x += addDeviceAttribute("Description", '<span onclick=p51editgroup(2) style=cursor:pointer>' + desc + ' <img class=hoverButton src="images/link5.png" /></span>');
+                x += addDeviceAttribute("Description", '<span onclick=p51editgroup(2,' + (currentUserGroup.membershipType != null) + ') style=cursor:pointer>' + desc + ' <img class=hoverButton src="images/link5.png" /></span>');
             } else {
                 x += addDeviceAttribute("Description", desc);
             }
@@ -15217,7 +15220,7 @@
             QH('p51group', x);
 
             x = '<br />';
-            if ((userinfo.siteadmin & 256) != 0) {
+            if ((currentUserGroup.membershipType == null) && ((userinfo.siteadmin & 256) != 0)) {
                 x += '<a href=# onclick="return p51showAddUserDialog()" style=cursor:pointer;margin-right:10px><img src=images/icon-addnew.png border=0 height=12 width=12> ' + "Add Users" + '</a>';
             }
             x += '<table style="color:black;background-color:#EEE;border-color:#AAA;border-width:1px;border-style:solid;border-collapse:collapse" border=0 cellpadding=2 cellspacing=0 width=100%><tbody><tr style=background-color:#AAAAAA;font-weight:bold><th scope=col style=text-align:left;width:430px>' + "Group Members" + '</th><th scope=col style=text-align:left></th></tr>';
@@ -15235,7 +15238,8 @@
 
             // Display all users for this user group
             for (var i in sortedusers) {
-                var trash = '<a href=# onclick=\'return p51deleteUser(event,"' + encodeURIComponentEx(sortedusers[i].id) + '")\' title="' + "Remove user rights to this device group" + '" style=cursor:pointer><img src=images/trash.png border=0 height=10 width=10></a>';
+                var trash = '';
+                if (currentUserGroup.membershipType == null) { trash = '<a href=# onclick=\'return p51deleteUser(event,"' + encodeURIComponentEx(sortedusers[i].id) + '")\' title="' + "Remove user rights to this device group" + '" style=cursor:pointer><img src=images/trash.png border=0 height=10 width=10></a>'; }
                 var username = EscapeHtml(decodeURIComponent(sortedusers[i].name));
                 if (users != null) { username = '<a href=# onclick=\'gotoUser("' + encodeURIComponentEx(sortedusers[i].id) + '");haltEvent(event);\'>' + username + '</a>'; }
                 x += '<tr ' + (((count % 2) == 0) ? 'style=background-color:#DDD' : '') + '><td><div title="' + "User" + '" class=m2></div><div>&nbsp;' + username + '<div></div></div></td><td><div style=float:right>' + trash + '</div></td></tr>';
@@ -15294,7 +15298,7 @@
             if (count == 1) { x += '<tr><td><div style=padding:6px>&nbsp;<i>' + "No devices in common" + '</i><div></div></div></td><td></td></tr>'; }
             x += '</tbody></table>';
 
-            if ((userinfo.siteadmin & 256) != 0) {
+            if (((currentUserGroup.membershipType == null) || (usercount == 0)) && ((userinfo.siteadmin & 256) != 0)) {
                 x += '<div style=font-size:small;text-align:right><span><a href=# onclick=p51showDeleteUserGroupDialog() style=cursor:pointer>' + "Delete User Group" + '</a></span></div>';
             }
 
@@ -15349,9 +15353,9 @@
             meshserver.send({ action: 'removemeshuser', meshid: meshid, userid: currentUserGroup._id });
         }
 
-        function p51editgroup(focus) {
+        function p51editgroup(focus, nameReadOnly) {
             if (xxdialogMode) return;
-            var x = addHtmlValue("Name", '<input id=dp51name style=width:230px maxlength=32 onchange=p51editgroupValidate() onkeyup=p51editgroupValidate(event) />');
+            var x = addHtmlValue("Name", '<input id=dp51name style=width:230px maxlength=32 onchange=p51editgroupValidate() onkeyup=p51editgroupValidate(event) ' + (nameReadOnly ? 'readonly disabled' : '') + '/>');
             x += addHtmlValue("Description", '<div style=width:230px;margin:0;padding:0><textarea id=dp51desc maxlength=1024 style=width:100%;resize:none></textarea></div>');
             setDialogMode(2, "Edit User Group", 3, p51editgroupEx, x);
             Q('dp51name').value = currentUserGroup.name;
@@ -15893,7 +15897,7 @@
                 if ((userinfo.siteadmin & 256) != 0) {
                     var userGroupCount = 0, newUserGroup = false;
                     for (var i in usergroups) {
-                        if (usergroups[i]._id.split('/')[1] != currentUser._id.split('/')[1]) continue;
+                        if ((usergroups[i].membershipType != null) || (usergroups[i]._id.split('/')[1] != currentUser._id.split('/')[1])) continue;
                         userGroupCount++;
                         if ((currentUser.links == null) || (currentUser.links[i] == null)) { newUserGroup = true; }
                     }
@@ -15911,7 +15915,7 @@
                             groupname = EscapeHtml(group.name);
                             if (usergroups != null) { groupname = '<a href=# onclick=\'gotoUserGroup("' + encodeURIComponentEx(ougroups[i]._id) + '");haltEvent(event);\'>' + groupname + '</a>'; }
                         }
-                        if ((userinfo.siteadmin & 256) != 0) { trash = '<a href=# onclick=\'return p30RemoveUserGroup(event,"' + encodeURIComponentEx(ougroups[i]._id) + '")\' title="' + "Remove user group membership" + '" style=cursor:pointer><img src=images/trash.png border=0 height=10 width=10></a>'; }
+                        if ((group.membershipType == null) && ((userinfo.siteadmin & 256) != 0)) { trash = '<a href=# onclick=\'return p30RemoveUserGroup(event,"' + encodeURIComponentEx(ougroups[i]._id) + '")\' title="' + "Remove user group membership" + '" style=cursor:pointer><img src=images/trash.png border=0 height=10 width=10></a>'; }
                         x += '<tr ' + (((++count % 2) == 0) ? 'style=background-color:#DDD' : '') + '><td><div title="' + "User Group" + '" class=m4></div><div>&nbsp;' + groupname + '<div></div></div></td><td><div style=float:right>' + trash + '</div></td></tr>';
                     }
                 }
@@ -15986,7 +15990,7 @@
             if (xxdialogMode || (usergroups == null)) return;
             var y = '';
             for (var i in usergroups) {
-                if (usergroups[i]._id.split('/')[1] != currentUser._id.split('/')[1]) continue;
+                if ((usergroups[i].membershipType != null) || (usergroups[i]._id.split('/')[1] != currentUser._id.split('/')[1])) continue;
                 if ((currentUser.links == null) || (currentUser.links[i] == null)) { y += '<option value=' + encodeURIComponentEx(i) + '>' + EscapeHtml(usergroups[i].name) + '</option>'; }
             }
             var x = addHtmlValue("User Group", '<div style=width:230px;margin:0;padding:0><select id=dp2groupid style=width:100%>' + y + '</select></div>');
diff --git a/webserver.js b/webserver.js
index 079fe5bc..b40ce53e 100644
--- a/webserver.js
+++ b/webserver.js
@@ -472,21 +472,18 @@ module.exports.CreateWebServer = function (parent, db, args, certificates, doneF
                 if (username == null) { username = shortname; }
                 var userid = 'user/' + domain.id + '/' + shortname;
 
+                // Get the list of groups this user is a member of.
+                var userMemberships = xxuser[(typeof domain.ldapusergroups == 'string') ? domain.ldapusergroups : 'memberOf'];
+                if (typeof userMemberships == 'string') { userMemberships = [userMemberships]; }
+                if (Array.isArray(userMemberships) == false) { userMemberships = []; }
+
                 // See if the user is required to be part of an LDAP user group in order to log into this server.
                 if (typeof domain.ldapuserrequiredgroupmembership == 'string') { domain.ldapuserrequiredgroupmembership = [domain.ldapuserrequiredgroupmembership]; }
                 if (Array.isArray(domain.ldapuserrequiredgroupmembership) && (domain.ldapuserrequiredgroupmembership.length > 0)) {
-                    // We must be part of a LDAP user group, lets get the list of groups this user is a member of.
-                    const memberOfKey = (typeof domain.ldapusergroups == 'string') ? domain.ldapusergroups : 'memberOf';
-                    var userMemberships = xxuser[memberOfKey];
-                    if (typeof userMemberships == 'string') { userMemberships = [userMemberships]; }
-                    if (Array.isArray(userMemberships) == false) { userMemberships = []; }
-
                     // Look for a matching LDAP user group
                     var userMembershipMatch = false;
                     for (var i in domain.ldapuserrequiredgroupmembership) { if (userMemberships.indexOf(domain.ldapuserrequiredgroupmembership[i]) >= 0) { userMembershipMatch = true; } }
-
-                    // If there is no match, deny the login
-                    if (userMembershipMatch === false) { fn('denied'); return; }
+                    if (userMembershipMatch === false) { fn('denied'); return; } // If there is no match, deny the login
                 }
 
                 // Get the email address for this LDAP user
@@ -578,6 +575,9 @@ module.exports.CreateWebServer = function (parent, db, args, certificates, doneF
                     // Indicate that this user has a image
                     if (userimage != null) { user.flags = 1; }
 
+                    // Synd the user with LDAP matching user groups
+                    if (syncExternalUserGroups(domain, user, userMemberships, 'ldap') == true) { userChanged = true; }
+
                     obj.users[user._id] = user;
                     obj.db.SetUser(user);
                     var event = { etype: 'user', userid: user._id, username: user.name, account: obj.CloneSafeUser(user), action: 'accountcreate', msgid: 128, msgArgs: [user.name], msg: 'Account created, name is ' + user.name, domain: domain.id };
@@ -612,6 +612,9 @@ module.exports.CreateWebServer = function (parent, db, args, certificates, doneF
                     if ((userimage != null) && ((user.flags == null) || ((user.flags & 1) == 0))) { if (user.flags == null) { user.flags = 1; } else { user.flags += 1; } userChanged = true; }
                     if ((userimage == null) && (user.flags != null) && ((user.flags & 1) != 0)) { if (user.flags == 1) { delete user.flags; } else { user.flags -= 1; } userChanged = true; }
 
+                    // Synd the user with LDAP matching user groups
+                    if (syncExternalUserGroups(domain, user, userMemberships, 'ldap') == true) { userChanged = true; }
+
                     // If the user changed, save the changes to the database here
                     if (userChanged) {
                         obj.db.SetUser(user);
@@ -8694,5 +8697,99 @@ module.exports.CreateWebServer = function (parent, db, args, certificates, doneF
         return r;
     }
 
+    // Sync an account with an external user group.
+    // Return true if the user was changed
+    function syncExternalUserGroups(domain, user, userMemberships, userMembershipType) {
+        var userChanged = false;
+        if (user.links == null) { user.links = {}; }
+
+        // Create a user of memberships for this user that type
+        var existingUserMemberships = {};
+        for (var i in user.links) {
+            if (i.startsWith('ugrp/') && (obj.userGroups[i] != null) && (obj.userGroups[i].membershipType == userMembershipType)) { existingUserMemberships[i] = obj.userGroups[i]; }
+        }
+
+        // Go thru the list user memberships and create and add to any user groups as needed
+        for (var i in userMemberships) {
+            const membership = userMemberships[i];
+            var ugrpid = 'ugrp/' + domain.id + '/' + obj.crypto.createHash('sha384').update(membership).digest('base64').replace(/\+/g, '@').replace(/\//g, '$');
+            var ugrp = obj.userGroups[ugrpid];
+            if (ugrp == null) {
+                // This user group does not exist, create it
+                ugrp = { type: 'ugrp', _id: ugrpid, name: membership, domain: domain.id, membershipType: userMembershipType, links: {} };
+
+                // Save the new group
+                db.Set(ugrp);
+                if (db.changeStream == false) { obj.userGroups[ugrpid] = ugrp; }
+
+                // Event the user group creation
+                var event = { etype: 'ugrp', ugrpid: ugrpid, name: ugrp.name, action: 'createusergroup', links: ugrp.links, msgid: 69, msgArgv: [ugrp.name], msg: 'User group created: ' + ugrp.name, ugrpdomain: domain.id };
+                parent.DispatchEvent(['*', ugrpid, user._id], obj, event); // Even if DB change stream is active, this event must be acted upon.
+
+                // Log in the auth log
+                if (parent.authlog) { parent.authLog('https', 'Created ' + userMembershipType + ' user group ' + ugrp.name); }
+            }
+
+            if (existingUserMemberships[ugrpid] == null) {
+                // This user is not part of the user group, add it.
+                if (user.links == null) { user.links = {}; }
+                user.links[ugrp._id] = { rights: 1 };
+                userChanged = true;
+                db.SetUser(user);
+                parent.DispatchEvent([user._id], obj, 'resubscribe');
+
+                // Notify user change
+                var targets = ['*', 'server-users', user._id];
+                var event = { etype: 'user', userid: user._id, username: user.name, account: obj.CloneSafeUser(user), action: 'accountchange', msgid: 67, msgArgs: [user.name], msg: 'User group membership changed: ' + user.name, domain: domain.id };
+                if (db.changeStream) { event.noact = 1; } // If DB change stream is active, don't use this event to change the user. Another event will come.
+                parent.DispatchEvent(targets, obj, event);
+
+                // Add a user to the user group
+                ugrp.links[user._id] = { userid: user._id, name: user.name, rights: 1 };
+                db.Set(ugrp);
+
+                // Notify user group change
+                var event = { etype: 'ugrp', userid: user._id, username: user.name, ugrpid: ugrp._id, name: ugrp.name, desc: ugrp.desc, action: 'usergroupchange', links: ugrp.links, msgid: 71, msgArgs: [user.name, ugrp.name], msg: 'Added user(s) ' + user.name + ' to user group ' + ugrp.name, addUserDomain: domain.id };
+                if (db.changeStream) { event.noact = 1; } // If DB change stream is active, don't use this event to change the user group. Another event will come.
+                parent.DispatchEvent(['*', ugrp._id, user._id], obj, event);
+            } else {
+                // User is already part of this user group
+                delete existingUserMemberships[ugrpid];
+            }
+        }
+
+        // Remove the user from any memberships they don't belong to anymore
+        for (var ugrpid in existingUserMemberships) {
+            var ugrp = obj.userGroups[ugrpid];
+            if ((user.links != null) && (user.links[ugrpid] != null)) {
+                delete user.links[ugrpid];
+
+                // Notify user change
+                var targets = ['*', 'server-users', user._id, user._id];
+                var event = { etype: 'user', userid: user._id, username: user.name, account: obj.CloneSafeUser(user), action: 'accountchange', msgid: 67, msgArgs: [user.name], msg: 'User group membership changed: ' + user.name, domain: domain.id };
+                if (db.changeStream) { event.noact = 1; } // If DB change stream is active, don't use this event to change the user. Another event will come.
+                parent.DispatchEvent(targets, obj, event);
+
+                db.SetUser(user);
+                parent.DispatchEvent([user._id], obj, 'resubscribe');
+            }
+
+            if (ugrp != null) {
+                // Remove the user from the group
+                if ((ugrp.links != null) && (ugrp.links[user._id] != null)) {
+                    delete ugrp.links[user._id];
+                    db.Set(ugrp);
+
+                    // Notify user group change
+                    var event = { etype: 'ugrp', userid: user._id, username: user.name, ugrpid: ugrp._id, name: ugrp.name, desc: ugrp.desc, action: 'usergroupchange', links: ugrp.links, msgid: 72, msgArgs: [user.name, ugrp.name], msg: 'Removed user ' + user.name + ' from user group ' + ugrp.name, domain: domain.id };
+                    if (db.changeStream) { event.noact = 1; } // If DB change stream is active, don't use this event to change the user group. Another event will come.
+                    parent.DispatchEvent(['*', ugrp._id, user._id], obj, event);
+                }
+            }
+        }
+
+        return userChanged;
+    }
+
     return obj;
 };