How do I force the pathfinding to take the right road

Hi guys, here's the deal :

'im trying to make some kind of AI with the pathfinding object but i want it to take some paths ONLY in a determined direction.

Something like "you can only take this road from that point, to go in that direction"

I don't know if i'm clear enough so i made this little drawing in paint to show you what i mean.

Is it even possible with the pathfinding plugin ? if not how else could i do ?

I just can't figure it out myself please help me :'(

Why not try making some solid objects putting them where you need and set the opacity to 0 so they cant be seen by people playing the game ????

because it would take the easiest/closest way, and not the right one. i guess my example was not good.

here is another one : let's say there are 2 escalators, one that goes up and on that goes down, if the AI needs to go down i want it to select the escalator that goes down and not the closest or whatever.

dont give me answers like : "just make an invisible wall pop in front of the wrong escalator so it would have no choice but to take the right one"

i'm trying to make a puzzle game that as many objects trying to find their paths, if i do that some objects that should pass wouldn't be able to :/

Maybe set variables when overlapping with object (and working with other variables)? I've had a busy day and i'm having a hard time visualizing your problem concretely xD