Measure on merge dimension

Hi,

We have 2 queries, one from universe and another from excel.

Query1

Business Grp     Vendor     Expense

Query2

BusinessArea     Supplier     Qty

There are some Suppliers in query2 which are not present in query1 in vendor and some vendors are in query1 but not query2 suppliers.

I want to get

Expense Difference = Query1.vendor's expense - expense of matched vendors of query1 to Supplier's of query2

So how I can calculate expense where vendors are matching from query1 to query2.

Thanks,

Ankit