Will/Does Netcode Support A Host Build?

I recently learned about a game structure that some AAA games use where the single-player portion of a game will use the multiplayer code and a virtual server running on the player's device. I really like this idea since it allows you to use one set of code for everything and you are essentially forced to keep up the multiplayer code. Is this setup possible using the new Netcode system? I'm guessing it would work using a host style system that only allows one connection.