WSSQL query for multiple computers at once

Question

I can run normal searches just fine. Windows 7 won't let me add a network share to my local index, but I can query the remote index just fine. The problem is that I can't find a way to query two indexes at once. I was hoping that something like this would work:

SELECT System.ItemName 
FROM compA.SystemIndex, compB.SystemIndex 
WHERE SCOPE='file://compA/pathA' OR SCOPE='file://compB/pathB'

but it doesn't. For simple queries, I can query compA and compB separately and then merge the results myself, but I'm hoping for a better way. Anybody here have some experience with this?