By some silver of possibility, conider that there are planets that are not of the same size but significantly large that it couln't be called a satellite. They are extremely close near the with same rotations but they don't collide because they are in a stable revolution for aeons and they don't collide.
They are so close that it looks like the world from upside down but a lot farther apart, Closer than the moon but farther than it's highest point (something like Mt.Everest is to earth or Olympus Mons Mars.) That there is no possibility to go from one planet to another through solid ground.
With the gravitational tidal forces and all, is it possible that a river can flow between them or sort of a sea that connects the individual planets together?