Sorry but I'll share my one trick. Polaroid filters. Depending on the rotation I can do TV 1 or 2. Sorry, but I don't have a 3 pony trick ready.
I have 3 Samsung TVs, 2 LCDs and a Plasma, mounted together on the same wall. Unfortunately for me, they all can be operated with the same remote. I want to be able to turn just one of them on instead of all three at times but I don't know how. Any ideas of how to be able to have the TVs be on different frequencies?