As odd as I find it to be agreeing with PaulS (just kidding, Paul! :D), API mode makes this sort of thing much easier actually. There is a bit of a learning curve in understanding the object model implemented by the library, but there are good examples that come with the library. If you're not already aware, get it here: GitHub - andrewrapp/xbee-arduino: Arduino library for communicating with XBee radios in API mode