That is like what might happen if our expanding universe is merely an expanding arena in a greater universe. When two similar expanding arenas intersect and overlap, there would be a gravitational effect in the overlap space like what is described in the article as "dark flow". Please Register or Log in to view the hidden image! My view of cosmology would be that when two expanding arenas overlap, the gravitational attraction between the galaxies in the overlap would lead to future big crunches. Please Register or Log in to view the hidden image! These are just ideas appropriate to this OP for discussion.