Multiplayer Progress and Steam Invites

Looking into getting Steam Invites working to replace having to connect with an IP and port. In my experience, connecting via IP and port has always been a hit-or-miss thing to use. Sometimes it works flawlessly and other times you have to fiddle with opening ports or using Hamachi. I'd rather not. So using Steam's lobby and invite systems will help players connect to each other without having to worry about all of that. I figured that, since the game is only available on Steam, that I might as well limit the connections to only work through Steam Invites! If this doesn't work, I don't know what will! I don't want to have to revert this game to being singleplayer only unless I absolutely have no other choice.