So, one of my townies turns into a ghost to sell me goods in the Magic Realm

I truly wouldn't mind if they made sense though. Say if an NPC is a vendor in San Myshuno, I think the game should pick a different one for another map instead of letting me see the same Sim everywhere I go. I understand that one day he could be selling food, and the day after beverages, but I don't really want to see him bounce between maps and never roll in another Sim.