The receivers looked kinda' sealed, so I am wondering how easy they made it to configure them. In order to do the configuration Stan is talking about, you have to modify both the transmitters and receivers.
Here's some remotes using the same family of chips, the PT2262 & PT2272 with the same addressing scheme. The arrows point to their address programming jumper fields. For these, you have to solder a little jumper to either the High or Low bus bar next to the address pins. As shipped with all the pins floating, they're all addressed the same.