You could do the ‘normal’ connection of the Beam to your TV via its ARC port, and then it would play any appropriate sound fed to the TV’s many HDMI ports. 

Hi @Airgetlam ,

thank you for your reply, that would imply I use the TV set as PC monitor as well, right? I actually have a PC monitor, the TV set would be separated from that.

Maybe use the optical input and add an optical switch to choose your source?

You might need to look at something along the lines of an HDFury Diva. The problem you have is getting the ARC audio from your TV to the Sonos… I don’t know if a standard HDMI switch will do that. If it doesn’t then the Diva has multiple inputs and can push out the TV audio signal. It can also auto-sense if that’s important.