Advanced Filter problem

In Excel 2003, I'm running an Advanced filter on 2 columns. One of them is a listing of Regions, one is a listing of Projects that uses initials - R, RH, D, DRH, H, DH, etc. I want to look at Central region working on R project and the Eastern region working on the DH project. The result I get gives me what I've asked for, but I also get RH in the Projects column, which I didn't ask for. I only want to see R. How can I be more specific with my filter? Thanks.