Is it possible to establish communication between them?
No. You can establish communication between the Arduino and the XBee, and between the Arduino and the WiFi shield, but the XBee can not talk to the WiFi shield directly.
Is it possible to establish communication between them?
No. You can establish communication between the Arduino and the XBee, and between the Arduino and the WiFi shield, but the XBee can not talk to the WiFi shield directly.