--- C:/Users/jmlsteele/AppData/Local/Temp/observer.php-revBASE.svn001.tmp.php	Mon Nov 18 14:50:44 2013
+++ S:/SVN/moodle/2.6/trunk/moodle/mod/forum/classes/observer.php	Mon Oct 27 11:49:44 2014
@@ -72,7 +72,7 @@
         require_once($CFG->dirroot . '/mod/forum/lib.php');
 
         $userid = $event->relateduserid;
-        $sql = "SELECT f.id, cm.id AS cmid
+        $sql = "SELECT f.id, cm.id AS cmid, cm.groupingid
                   FROM {forum} f
                   JOIN {course_modules} cm ON (cm.instance = f.id)
                   JOIN {modules} m ON (m.id = cm.module)
@@ -85,6 +85,13 @@
 
         $forums = $DB->get_records_sql($sql, $params);
         foreach ($forums as $forum) {
+            // If the forum uses groupings and the user isn't part of the grouping don't subscribe.
+            if ($forum->groupingid != 0) {
+                $members = groups_get_grouping_members($forum->groupingid, 'u.id');
+                if (!array_key_exists($userid, $members)) {
+                    continue;
+                }
+            }
             // If user doesn't have allowforcesubscribe capability then don't subscribe.
             if (has_capability('mod/forum:allowforcesubscribe', context_module::instance($forum->cmid), $userid)) {
                 forum_subscribe($userid, $forum->id);