You can try using a "I" series remote and antenna in one room.  They are 433 MHz versus 418 MHz on the regular series.. URC RF opens a gateway that accepts all signals in their frequency for a set amount of time (forget exactly how long).

I had a client that moved from the city where the 433 MHz is commonplace and we installed it along with a new 418 MHz in another room.  I wasn't aware they had the i series until time of install, so tested it, being I was of the believe that the gateway would be open and accept signal no matter which frequency it was on.  I did not experience the issue when testing.