J.B.
I actually have 2 Fisher Price Lights & Sounds monitors and they seem to work fine together. I have been using them both for about 5 months. In that amount of time, there have only been a few incidents when I could hear both kids through one monitor. Then all I had to do was move one and it stopped. Also, I do have one set to "A" and the other to "B". Hope this helps and good luck!