public function GetCountForRole($RoleID = '') {
      if (!is_array($RoleID))
         $RoleID = array($RoleID);
      
      return $this->SQL
         ->Select('a.ActivityID', 'count', 'ActivityCount')
         ->From('Activity a')
         ->Join('ActivityType t', 'a.ActivityTypeID = t.ActivityTypeID')
         ->Join('UserRole ur', 'a.ActivityUserID = ur.UserID')
         ->WhereIn('ur.RoleID', $RoleID)
         ->Where('t.Public', '1')
         ->Get()
         ->FirstRow()
         ->ActivityCount;
   }