IR controls

I am trying to control one arduino with another using IR, however I can't seem to find any resources on how to build the messages correctly. There are a lot of things with remotes, but not a lot on building your own.

Basically I think I need a way to communicate with multiple arduinos without fear of stray IR light triggering and being able to send different messages. i.e. trigger led 1, led 2, led 2 on arduino #2 with just IR on arduino #1

any suggestions on what to read up on?