Here is an image of what I'm trying to do. In my research it seems like a sound mixer will handle the audio from the computers and TV so I can have some or all of them going to the headset. I haven't found much on having the microphone from the headset going back to the computers. Is that possible? Having to toggle a switch on a mixer to send it to one or the other is fine.
Also, the laptops have a single port for both input and output. I presume I can use some adapter to deal with that though, right?