OT: 2x 5.1 on a boxing system

Ahoihoi, don’t know if I’m right here (doesn’t have anything to do with a car), I’ll try it anyway! As in the title, I want to hang ZWEI existing 5.1 sources (PC & DVD player) on A 5.1 boxing system (everything connected by chinch). Is there any switch at all for this? Or another trivial solution? Have just Googled, but apparently nobody has such a “problem”?! Even iB doesn’t have such a thing! The idea is not so absurd, does it? Thanks already – furby