Help? Warp

[Vipes]

I have a small problem. I want this part of the level to seem like the player is going through the same hallway many times. I did that part. However, I want the door behind the player to slam shut once the player inters another hallway. If the player opens it up again he is looking at the room connected to A, and if he walks into it, he goes in the room. However if he never opens the door that closed, he continues normally until he reaches the true end.