The only way something like that is going to work is with a full system that uses back-end control processors to manage everything. I would imagine you'd be looking at the bare minimum of $1500 for a basic system with two of the cheapest controls, plus programming (it would not be do-it-yourself).

Otherwise, I would suggest foregoing the full synchronization idea and accepting something that will at least work; ie. traditional remotes (non-activity) that aren't trying to outsmart the other one to the point that neither work. :-)