I have 2 spreadsheets that both contain store numbers and the accounts they
belong to. I want to compare the two files to make sure that all of the store
numbers in one (smaller) list are included in the other (master) list.

I usually use the VLOOKUP formula to search for the store numbers in the
small file and return the same values in the master file. In this instance,
some of my store numbers are duplicated across accounts. For example, ABC
retailer and XYZ retailer might both have a store #123.

I want to do the same thing I have been doing with the previous VLOOKUPS,
but restrict my queries to the specific account. In other words, I want to
VLOOKUP store #123 but only where account = ABC.