Restricting played sims from showing up on lots outside their world?

I looked to see if it was giving sims a hidden trait, that I then hoped to use cheats to apply to other sims to move them around as desired - but no luck there as yet.

It doesn't, it just checks in which region the Sims live. I use a similar method in my townieoverhaul_lessfame, but to a smaller extend because I don't like random generation of townies that aren't specific role sims.