Four HR20-100 How Do I 00001 Etc On the Remote Control

I have four HR20-100 on a whole house system. I switched the remote codes in the set-up menu to 00001, 00002, 00003, and 00004 so they will all work independently. But how do I get the remote controls to talk to the appropriate box? What key sequence do I have to press on the remote to get the 00001 remote to just talk to the 00001 box? What key sequence do I have to press to get the 00002 remote to just talk to the 00002 box? Etc. Thanks!