Sorry for late reply. And sorry but I don't think I could do this.
The thing is, usually this type of zones in games is made with sstatic invisible 3d trigger objects that are created by a level designer right inside the scene/map editor. And then, in code, we could check if the player is inside the trigger box or not (just like we check if the player is underwater for example, which is also made via an invisible 3d boxes placed into the water area). This method in general uses engine features such as physics engine and collision detection, and it's relatively fast is this case.
There's also a bit different method. Just casting a virtual box at the given position/rotation and check if the player is inside the box.
Both methods would require to think a lot about how exactly describe these box/triangle shaped zones in the mod settings and make it relatively easy to set up. Honestly, I have no idea how I would do that.
In other words, it's just too much work and no guarantee that it wlll work well in the end.