Форум

AddEventHandler("iblock", "OnBeforeIBlockElementUpdate","SaveMySection");
function SaveMySection(&$arFields)
{
    if (@$_REQUEST['mode']=='import')//импорт  из 1с?
    {
        $db_old_groups = CIBlockElement::GetElementGroups($arFields['ID'], true);
        while($ar_group = $db_old_groups->Fetch())
        {
            if(!in_array($ar_group['ID'],$arFields['IBLOCK_SECTION']))
            $arFields['IBLOCK_SECTION'][]=$ar_group['ID'];
        }
    }
}