I did some checking and your receiver doesn't have any audio outputs other than the speaker outs. You could use a headphone output if it had one but it doesn't, and to add headphone functionality you'd have to purchase a wireless unit called the "S-AIR".
You could feed the audio signals of each of your components into an analog switcher box and have one cable coming out of the box going in to the wireless headphone's base unit. This would probably be the easiest and most inexpensive way to connect the headphones.
Al at ZVOX Audio
would like to secure some info as to connecting my sennheiser 120 wirelesss headsets to my Sony HT-SS320 home theater receiver , which carries the audio signal for my TV, Blu-ray and X-box..all audio out ports seem to be in use including the optical audio out port, along with all the HDMI ports...is this possible?