Mars or Ceres multiplayer?

After lots of drill, I've beaten the computer enough to fling myself into the multiplayer shark tank.  Imagine my surprise and disappointment to find myself on the unfamiliar ground of Ceres.  While I fully expected to lose my first game, this was a waste of my time, a waste of Somethinginfinite's time (which I regret), and a real wet blanket on what should have been a thrill.

 

If there's any way to restrict the engine to assigning players only to Martian or Cerean multiplayer games, I couldn't find it.  That option needs to be either installed or made a lot more visible.  Mastering the basics of vanilla OTC has been difficult enough; I'd like a chance to play that before being called upon to buy and master an expansion in order to join the community.  Because OTC is a great game--one with an intimidating learning curve that warrants making room for slower players and late arrivals.