How to Get Individual Instance Position in Material (Instanced Static Mesh)

How can I get each Instanced Static Mesh instance’s Z offset/position information inside a material or Blueprint, and subtract it from World Position Offset (WPO) so every instance uses its own local bottom shadow/mask instead of sharing one global value?

This logic works on regular Static Meshes. I need the same logic to work on Instanced Static Meshes as well.

GetPrimitiveData(Parameters).InstanceLocalBoundsCenter.xyz

GetPrimitiveData(Parameters).InstanceLocalBoundsExtent.xyz