Well one way you could implement something like that is to not allow trades.
This scenario is no longer on my top list of priorities. My first priority is still getting my ACW scenario out of Beta. And I've also started a new adventurous project, of getting a few scores on the Hall of Fame. And, I'm getting alot of good, positive feedback on my Late Han Dynasty/Three Kingdoms Scenario (more support overall so far than this one, except for Steph and BAP in particular), that I think that one will be first. More likely though, when I get to the one, I'll start the other as well.
But I will need more information, and I haven't really had the time to dig more information up yet.