You should not need to change the ERF configurations. Everything sent from one ERF will be received by every other ERF on that same frequency, same channel and with the same PAN ID.
There would be no knowledge of who was sending or where the data was directed so this would need to be added to the data being sent using an ID of sender and/or receiver.
You could alternatively program each sending ERF with a different frequency, channel number or PAN ID. You would need to have the receiver alter itself to match each transmitter in turn.