As of writing this, there is no way inside of Roblox to transfer datastore saves/data between games*. Here are some things you may want to consider:
- Use place universes - if you don’t mind having the place you want to “interact” with inside the main place then you can use GlobalDatastore.
- Use HTTP service. I am not too experienced with this one, but I’m sure that if you look around on devforum there are some options.
As for gamepasses, the place that the gamepass belongs to is irrelevant because MarketplaceServer:UserOwnsGamePassAsync() works for all games.
P.S, please make sure that you search devforum before replying to topics. I made a topic on this a while back: How can I transfer data between games?
(* without using http)