I've never seen anyone talking about this #Doubt

Let's suppose I'm on any map, if I enter a Mist on that map, are the people who are with me in that Mist people who came directly from the same map I was on? Or are they people from several different maps?

I thought about this because, if it's from the same map, the ideal would be to go to a more distant map, find a Bruma and have less competition.