You can still get multiple tavs going its just different. I found a guide on steam that explained it, I'm not at the computer so I can't link.
Close down steam open the exe file location and shift left double click it, it'll skip launcher and run under Volcan. The guide said the basic exe but I don't know if 11 version will work also.
The game will run offline and go by lan or whatever, it'll be under multi-player when you go to create a character & host.
You might be able to ad tavs to a later game by the same method, untested though for me.
Have fun
