3D mp_potential_step_object, but excluding some instances?

I'm making a 3D game with height and vertical platforming, but i need enemies to navigate around objects while excluding the ones above and below them. Right now I have it set up so that I can make platforms using a single object that have ztop and zbot variables to adjust the height.

I'd like to use mp_potential_step_object, but I'd need a way to exclude the wall objects that are above and below the enemy. If this isn't possible I can use mp_grid_path, which I've already tried and it works, but it's more difficult to work with. I'm just wondering if there's a way to make mp_potential_step work instead.
Anyone have any ideas?
 
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