Try this:
Set Variable:[Player X] to Player's Screen X.
Set Variable:[Player Y] to Player's Screen Y.
Subtract Variable:[Player X] by [Next Map Width - 1] (ex. 20-wide map, subtract 19)
Set Variable:[Map ID] to Constant(whatever the next map id is) {found by map number, or hitting space on a map and getting the ID}
Teleport to [Player X], [Player Y], [Map ID]
You'd put this into one event and then copy it to every teleport square. The maps have to be the same height or correspond (Map 1 Upper right hand corner is next to Map 2 Upper Left hand corner).
I'm on my dad's laptop, so I can't test if it works yet.