Reply to Live Input on Deck C? Two versions of Traktor and two Kontrol S2's NEED Single output

My friend and I are djing together. We are using our own laptops and have sync'd our traktors via MIDI and an ethernet cable. As of right now, we have to run 2 lines of output to the speakers. We do not have a mixer to have in's with a single out but I had the thought of maybe being able to send the Slave's output into Master Computer so that It can go into Traktor as a live input? would that work? I have tried to do that and didn't have the best luck but I might have missed something. Any help to get us pointed in the single output combination would be awesome.