xbee series 1 three or four communication usb link

Hi, I downloaded a code to automate my observatory using 2 arduino and 2 xbee. That is fine. In this setup, 1 of the arduino is plugged into a computer to receive command from the planetarium software.
But in my observatory, that cannot be, because mechanicaly the motor is rotating 360 degre, if I hook a usb cable in this to communicate that will be a mess.
How can I replace the usb link with the communication arduino?
Can I add 1 xbee in a xbee explorer in the pc to communicate with the one other that communicate to the another?
Or can I replace the usb cable with 2 xbee with usb plug, one in usb-pc and the other in usb-Arduino?
Will that complicate the coding already done?
What will you do ?
Thank You