Sounds to me like you have rooms with 2 people in them...so 2 TVs each having its own cable box and universal remote.

I assume that the cable box remotes control the cable boxes via RF and the TVs via IR coming out of the remote or IR coming out of the cable box.

NOTE: Most TVs do not have RF communication capabilities so your universal remote cant control it over RF.

Maybe you are saying that the RF remotes are overlapping and cross talking? I have never seen this before even in large buildings with hundreds of people using cable box universal remotes.

Questions:

1. When you say "either both remotes control both TV's... or one remote controls both TV's." are you talking about the TV or the cable box? Are you able to use either remote to turn both TVs on and off and adjust volume? Or are you saying that you can change the channel on both cable boxes with either remote?

2. What model cable box and remote? I want to see if the remote can be set to IR only. If so you could try IR repeater systems with IR shields.

3. What is the room layout? Can you sketch a typical room out so i can see whether or not this will work. For example... if the 2 TVs are on the same wall close to each other then both remotes will most likely "hit" both IR receivers making the IR repeater system a waste of time.