"You should really go read the devblogs as you keep asking questions that have been answered in those. But no a market will probably be mostly local to itself with communication to other networks (from what I remember) so if your selling something at one market someone from another market might be able to see it but they would have to go pick it up or have it shipped to them. It could also be a private or local only market possibly though most mechanics are not really know for the game"
thanks for answering but the dev blog doesn't have a search function and I don't have the time to read them all