steambc
I am capitalizing on Dave X10 and Brian's suggestion, but regressing down the KISS road. You said you were only using the IR remotes to turn ON and OFF the individual AC units. So if you do not control fan speed, temp, etc with the remotes, you could hack both controls with X10 Universal modules for direct control of the AC IR remotes (rather than trying to get AH to send IR to the AC units).
If your remote has a single button (push once for ON, and a second push will turn AC OFF), then one Universal module for each IR remote would work. If the IRs have an ON and an OFF button, then you would need two Universal modules for each IR remote. The Universal module will provide a momentary closure which you would need to wire across the respective switch contacts in the IR remote.