Still not 100% sure what you're trying to do, but are you saying, how to make different auto-events run when you return to the previous map without having to use a key item?
If you simply want a different auto-run event to run when the player returns to a previous map, you can simply setup a switch in the event. When the player leaves that map, or when some conditions are met, you flip that switch so that the next time the player returns to the map, the auto-run event will determine which version it should run based on the switch condition.
Not sure if this is what you're looking for.