SQL is the considerably better spot for it.  If you have a GROUP BY in your query, you would just add a HAVING clause that specifies that all the SUMs are > 50.  Even if your query is dynamic SQL, you would already have to have the field list to do so, thus adding another snippet that takes each field and adds it to the HAVING clause isn't all that difficult.   As you may have already discovered, trying to filter that matrix isn't going to work so well.