Conditionally select validation

I am working on a project that allows a user to select a metting room. Once they select it passes the name of that room to the next page in a session. On that next page I have a textbox for the number of attendees. I added a range validator for each room each of which can accomodate a different max number of people. I would like to have only validator A enabled for RoomA and Validator B for Room B, etc. The other 3 range validators should be disabled.