Matchmaking without internet

Hello,
I’d like to create a game room on a local network for players to connect, either using the local wifi or using 4g.

This game requires all the users to be in the same physical space, so ideally I wouldn’t want to use the matchmaking service. They can be in a place without internet.

How can I do this without internet. Let’s say, if one of the users tells the ip to the other users, i can use HLAPI to connect them, right?
So it’s a matter of finding a intuitive way of sending the server’s ip to the other clients. Is it possible? How to do it?

Thanks

ps: is it a mistake to not use matchmaking in this case?

You can use NetworkDiscovery for that.