If we disable just the crusade DLC, we are able to play together. When I turn on crusade I can't join a lobby that both of them are in (both of them as well having crusade DLC turned on).
I bought Gal Civ 3 on steam back when it very first came out and came with the Builders Kit DLC, Map Pack DLC, Ship Parts Launch Pack, and Ship Designer's Toolbox DLC. Recently I've wanted to get back to the game and do some multiplayer with friends, so they bought the Gal Civ 3 pack that is currently on sale. It comes with Crusade, Mega Events, and Retribution. I didn't have those DLC so I went ahead and got the pack as well since its cheap at the moment. However, now when I host a multiplay