I hear you and my code already performs that same function.
Arduino A sends a code- then enablesIRin to hear If a code has been sent back. Then it loops and sends again - it's that when it loops the code being sent now is garbled and non decipherable by Arduino B. I understand the EnableIRin must always be called after irsend but I think the fact they both use the same timer causes some serious issues. I might try one of these methods ASAP