I'm hosting myself a singleplayer dynamic-grid server which is not on steam/atlas server list, but not on the lan list either. The only way to get is through favorites. I haven't tested it from my LAN and it's unlikely I will, but you can host it too. Just follow any server hosting guide (I recommend using Atlas Server Controller by ChromeSDK, makes it super easy to create and control your server, up to 9 static grids, or you can just swap on-off grids you need). Just instead of port forwarding(I don't think you need it for LAN?) go for loopback.
EDIT: Or just host yourself a normal server with those same guides, just make it password protected?