My mod I'm currently working on.

[Abion47]

You could add a collide area that just collides with everything, but then you'd run into issues because it collides with everything, including things you don't expect it to be colliding with. With keeping to neat organization and all around general sanity, it might be easier to just have two overlapping areas for the player and the monster each.

(Although, I think that most monsters have it built-in to their AI code that if a path node rests on top of a door, they will open the door themselves already.)