You'll need to also have your addons for Ulib/ULX for the local client.
Find two available Steam friends.
Set reserved slots to 1 in your local ULX server config.
Start a listen server, server max players 2.
You can set a password so no one but your friends know.
Have a non-admin friend join.
Few minutes later, have an admin friend join.
I'm sick today, not fully thinking clearly, but I would think that should work without having to use your dedicated.