The whole point of Carceri is that you're trapped there by your own spite; if someone were capable of working with others well enough to get out, they wouldn't be there in the first place.

The only thing Carceri's denizens want more than to escape, is to be the only one who escapes.
Now this does answer my question. Thanks!

Planescape doesn't have a "save or be stuck" effect for Carceri either, at least not in the Planescape Campaign Setting or Planes of Conflict which I just checked; Carceri is a prison for its petitioners in both editions, not just any berk who wanders by. Elysium and Hades have Entrapping traits in both editions, though.
Those who wanders by can use portals, but I read in lore books that locals always do their best to not allow anyone to use them. If they are trapped, why allow others to run away?