group by in SearchEngine

hi,

we want to auto-fill in Tickets the extra-field "Cost Center" (in Germn "Kostenstelle") depending on its Ticket Person (in German "Ansprechpartner"), because each person in our Company belongs to a certain Cost Center:

This Association is stored in our Active Directoary. But in crm scripts there is no Connection to our AD. My Idee will be, seach in all Tickets, what is the most Cost Center for that Person, this will be auto. filled in new Ticket. In SO Database, i reach that with SQL-Statement for my Person, important is here group by in SQL:

Now i want to convert it in SearchEngine in crm scripts,

but it posts me Runtime Error  by Using grouping.

Thanks!