XBee Relay questions

So… I am a student working at a university, and we are using the XBee chips to send data in a field site. One of our nodes is a little bit far away, so we wanted to construct some kind of relay to send the data. So… what I did was i just stuck a loopback on an XBee chip and said “its a relay now.”

see, my understanding was that whatever they received wirelessly, they sent serially, and whatever they receieved serially, they sent wirelessly (unless its the AT commands). So if you sent something to it wirelessly, it would send it to the serial connection, which, if there was a loopback on it, it would get right back, and then proceed to send wirelessly again to its destination address.

But some kind of weird packetization occurred, and i dont know why. Can someone tell me what part of this I am misunderstanding?