How to get digital surround sound audio from ps3 and pc at the same time?

[Groms]

Hi, I have the Astro a50 headphones in this configuration:
mixamp--->USB--->PC for just stereo audio and voice,
mixamp--->optical--->PS3 for 5.1 surround from PS3.

My question is, how would I get digital surround sound audio from both the PS3 and PC, and listen to them at the same time? Thanks!

 

[dottorrent]

You can't. Since the Astro A50s use Virtual Surround sound on a USB, you can't mix and match. Plus, one Coaxial audio cable, one device only.