Build/publish Two Copies At Once?

I'm looking for a way to have my code build two copies of itself at once.The program has an "A" and a "B" configuration that need to be compiled as Prog-A.exe and Prog-B.exe every time the code is compiled. I can do this manually, but I assume there's some way to do it in code? What I'd like is to use conditional compilation to have the A configuration compile so that it runs a "setup as A"-type method on load, and the B likewise, and then have it compile both versions each time.