Sorting irregular objects in 2D isometric view

Hi, we are developing 2D isometric RPG game. We thought we have sorting layers pretty much all sorted out (pun intended) by dynamically sorting objects along the Y axis.

On the first screen everything is correct - the character's position is below the building pivot and the character is in front of the building. But the problem appears when the object is above the pivot of another object - it should be then in front of that object but it isn't. You can see that on the second screen the character is behind the wall.

We can’t move the pivot any higher because then if our character go to the left - like “behind” the building - it is seen in front of the building which is wrong (third screen).

The solution that comes to our heads is to cut the object in parts and every such part would have its own pivot but we’re not sure that it would work well and it can be kinda troublesome for the graphic designer.

I think we have found and checked out almost all similar questions and different forums and no answer was satisfying. Do any of you guys have any idea or solution that could help us?

Thanks in advance :)

First screen: Second screen: Third screen: