Sorry, I am not sure if I am in the correct category. Also, I am a beginner so be kind

I have two Xbee-Pro 900HP radios. A router and a coordinator. The router has a GPS connected to it. The GPS coordinates xmit over to the Coordinator just fine. My question, is there a way to prefix the GPS datastream from the the Router to the Coordinator with the ID (or any unique identifier)? Eventually I would like to add additional Xbees with additional sensors. I need a way to identify what Router the data is coming from on the Coordinator. Any help would be greatly appreciated.