public function getAllTimezonesGrouped()
 {
     /**
      * @var Zend_Db_Table_Rowset
      */
     $timezoneGroups = $this->fetchAll();
     $timezoneGroups = $timezoneGroups->toArray();
     $timezone = new App_Timezone();
     foreach ($timezoneGroups as $key => $timezoneGroup) {
         $timezoneGroups[$key]["timezones"] = $timezone->fetchByTimezoneGroup($timezoneGroup["id"])->toArray();
     }
     return $timezoneGroups;
 }