Search Profile fields filter

I'm trying to use a "Search" filter on a table View that I've created that searches against profile.module fields
Problem is that, it seems to include this join:

LEFT JOIN my_custom_sindex_table search_index ON users.uid = search_index.sid

Except, my 'sid' field will never be a 'uid'. For profile.module, the profile_values table uses a combination of 'uid' and 'fid' (field id); thus, I've used this as my 'sid' in the index ('uid' . 'fid').

I tried looking in the Views module code, but can't find where to either 1) remove this join, or 2) somehow associate my View to a Search or Profile type rather than Node or User, or 3) change this query.