About 17 years ago my dad actually had our house set up like this. We had satellite, and the main home theater had a box of it's own, but there was one box in the basement that would broadcast to the three other spots in the house on channel 3 or whatever. We then had IR signal injectors on those three lines to control it. It was pretty cool stuff for the time, but it still meant watching the same thing on all three of those TVs.