communication between two Arduino thanks to a xbee Module

hellos,
I want to create a link between two Arduino son without grace has s1 xbee modules. I have already managed to create a reliable link between two Arduino directemant by communicating between my unit xbee connect to each Arduino. I wish now added a xbee but between two Arduino (in relay mode) in order to increase the distance between my TRANSMITTER module and receiver.

so my question is how should I xbee parameter but that communication works correctly?
Regards,