Конвертация переменной типа пользователь к типу привязка к сотруднику

/*
CONVERT CATEGORY USERS TO BP DIZAYNER FIELD USER (STRING)
 PARAM STRING
*/
function udgsToBpField($string){
   $string = explode(", ",mb_strtolower($string));
   $typesSearch = array("au","sg","iu","u","dr","d","g");
   $typesResult = array("au","group_sg","user_","user_","group_dr","group_d","group_g");
   for($i=0; $i < count($string); $i++){
      if(stristr($string[$i],$typesSearch[0]) !== FALSE){
         $string[$i] = str_replace($typesSearch[0],$typesResult[0],$string[$i]);
      } else if(stristr($string[$i],$typesSearch[1]) !== FALSE){
         $string[$i] = str_replace($typesSearch[1],$typesResult[1],$string[$i]);
      } else if(stristr($string[$i],$typesSearch[2]) !== FALSE){
         $string[$i] = str_replace($typesSearch[2],$typesResult[2],$string[$i]);
      } else if(stristr($string[$i],$typesSearch[3]) !== FALSE){
         $string[$i] = str_replace($typesSearch[3],$typesResult[3],$string[$i]);
      } else if(stristr($string[$i],$typesSearch[4]) !== FALSE){
         $string[$i] = str_replace($typesSearch[4],$typesResult[4],$string[$i]);
      } else if(stristr($string[$i],$typesSearch[5]) !== FALSE){
         $string[$i] = str_replace($typesSearch[5],$typesResult[5],$string[$i]);
      } else if(stristr($string[$i],$typesSearch[6]) !== FALSE){
         $string[$i] = str_replace($typesSearch[6],$typesResult[6],$string[$i]);
      }
   }
   return $string;
}