A relevant question to both teams, would you prefer if you are in the same "reality" and so each party's actions can influence the other, like if one team saves/destroys/loots a place and the other party arrives there later there'll be not much left to do, including all the way to the parties meeting and fighting, or would you rather be in alternate "timelines" so each campaign is independent from the other in which case I'll still include the other party as rival NPCs with alternate personalities under my control.