It is very easy. Many people do this mistake. On collision with with door 1 ---> go to door 2
then they do on collision with door 2 --> go to door 1
See the problem?
This creates a loop. When you collide with door 1 you go to door 2 and you collide with that one as soon as your player is there and you'll end up teleporting back and forth between the doors endlessly. So you have to think how to prevent it.
Here is a fast solution for it: https://1drv.ms/u/s!AowQiuoNUifdid0yIAU1IHBag5HedA
There are many ways of doing it and if I do doors I create a family and create events once for the whole family and not for every single door.
But the idea is:
1. Have a bool on the player "canPassDoor"
2. on collision with door and is canPassDoor = true ---> set canPassDoor to false and then move the player to the other door
3. And after the player has teleported to the new door then set canPassDoor back to true again
This prevents the player from teleporting back and forth as the variable is false when the collision with the next door is triggered.