Howdy med stud!
Maybe they have Teleport Circles or Permanent Gates in Hell.
The idea that every demon or devil can teleport and many can plane shift takes away from the classic "We have to destroy the portal to stop the [insert threat] coming through."
In Hell (or wherever) where the devils have centuries if not millenia to establish and defend these portals then it makes sense every devil fortress (or immortal's divine realm) will have a "Gate Room" not to get too Stargate-y.
So while it may be a ritual to create the portal in the first place I don't think it will require a ritual everytime you want to use one.