[Quikngruvn]

Quikngruvn:
Hmm... possibly. Those also wouldn't apply to "underground" cities. Perhaps something else could be done with the 3 planet compositions?

Hmm... since cities will be subjugated, not colonized, perhaps make each atmosphere correlate to a certain deity that the indigenous populations and the players' empires worship. An indigenous population would tolerate many more player-empire citizens that share their same belief system than those who don't.... (You could make the same case with alignment as well.)

Quikngruvn