Ethnicities aka Stop Spawning Judith Ward in Mt Komorebi

hey she's a rich sim so if she can afford a trip to japan then i ain't gonna stop her

jokes aside, devs could just limit the people from a world to just roam on the world they're in, whoever it is, whoever you put. the sims themselves have no real ethnicities and trying to make this idea canon on the game would be a big mistake & controversy fuel.