Возможно ли реализовать через инфоблок
$filter = Array("LOGIN_EQUAL"=> $ar["HEAD"]);
$reshead = CUser::GetList(($by="id"), ($order="desc"), $filter, array("SELECT"=>array("UF_*"), "FIELDS"=>array("ID","LOGIN")));
while($arhead = $reshead->fetch()){
if($arhead["LOGIN"]==$ar["HEAD"])
$head_id = $arhead["ID"];
}
$resSectionFind = CIBlockSection::GetList(Array(), array("IBLOCK_ID"=>3,"XML_ID"=>$ar["XML_ID"]), Array("nPageSize"=>1), array("ID"));