DaveO:
So are you saying that the normal loop would bypass the rf code, until the loop detects incoming data ? And at that point, it would execute the rf section of code and when that is completed, would then continue with the rest of the sketch ?
Yes, if I understood you correctly. It will evaluate radio.available() repeatedly, and it will only execute the body of the 'if' statement when radio.available() indicates that there is a message available.