Stream multiple games at once w/ Steam

I've been trying to figure out a way to make this work for the past days, yet I could not come up with a good solution. I have a friend who currently lives in Portugal. We've been trying to play a game called Hearts of Iron IV, a strategy game basically. I have a great PC, that's suitable to run the game multiple times, however he has a trash laptop, and we caot play the game together. We tested Steam in-home streaming through Hamachi and it works like a charm. I'm wondering if there is a way to stream the game through Steam in-home streaming, so that both of us can play it, because currently, Steam in-home streaming opens the game, and I caot alt-tab out or anything like that. Thanks in advance.