Index: trunk/core/units/groups/groups_event_handler.php
===================================================================
diff -u -N -r6625 -r7635
--- trunk/core/units/groups/groups_event_handler.php	(.../groups_event_handler.php)	(revision 6625)
+++ trunk/core/units/groups/groups_event_handler.php	(.../groups_event_handler.php)	(revision 7635)
@@ -9,9 +9,28 @@
 		 */
 		function SetCustomQuery(&$event)
 		{
-			if ($event->Special == 'total') {
 				$object =& $event->getObject();
+			/* @var $object kDBList */
+			
+			switch ($event->Special) {
+				case 'total':
 				$object->AddGroupByField('%1$s.GroupId');
+					break;
+			
+				case 'user':
+					$user_id = $this->Application->GetVar('u_id');
+					if ($user_id !== false) {
+						// show only groups, that user doesn't belong to
+						$table_name = $this->Application->GetTempName(TABLE_PREFIX.'UserGroup', 'prefix:u');
+						$sql = 'SELECT GroupId
+								FROM '.$table_name.'
+								WHERE PortalUserId = '.$user_id;
+						$group_ids = $this->Conn->GetCol($sql);
+						array_push($group_ids, 14, 15); // Guest & Everyone groups are set dynamically
+						
+						$object->addFilter('already_member_filter', '%1$s.GroupId NOT IN ('.implode(',', $group_ids).')');
+					}
+					break;
 			}
 		}
 	}