private function addRecipientsFilter(Gpf_SqlBuilder_Filter $filter)
 {
     $condition = new Gpf_SqlBuilder_CompoundWhereCondition();
     $condition->add('m.' . Gpf_Db_Table_Mails::TO_RECIPIENTS, '=', $filter->getValue(), 'OR');
     try {
         $dbUser = new Gpf_Db_AuthUser();
         $dbUser->setUsername($filter->getValue());
         $dbUser->loadFromData(array(Gpf_Db_Table_AuthUsers::USERNAME));
         if (strlen($dbUser->getNotificationEmail())) {
             $condition->add('m.' . Gpf_Db_Table_Mails::TO_RECIPIENTS, '=', $dbUser->getNotificationEmail(), 'OR');
         }
     } catch (Exception $e) {
     }
     $this->_selectBuilder->where->addCondition($condition);
 }