I use two sets in my house, and I don't have a problem with them.

Even if they use the same frequency (not sure if they do or not), I'm controlling different brands/models/types of components with each receiver, so it doesn't matter. I don't need to isolate the signals from each other.

The only time you would have a problem is if you had two of the same exact brand/model of stereo or TV (one at each end of the equation) and you did not want both of them to be simultaneously controlled by the remote.