Pale Moors Hogwarts Express

[Sasuke Uchiha]

From the rules:

As long as you've synced with the recall station once in person, you can simply get in touch via your Communicator and be warped back home.

So, I dunno what you mean about "not being on the list", but it can only bring people to you who have already been there.

Well outposts and secondaries can have communicators if you hook up a stationary communicator to the recall device. You could do that for whoever has the access to said station. Or at least that's my logic.

People can't sync the recall for you. You must sync it yourself, in person first, before being able to use it.