Dynamic material in world partition HLOD?

I’m making something similar to the City Sample, only I want the lights in the windows of the buildings turn on and off. I’m controlling it by blending emissive output in material.

The problem is with HLOD, it generates merged and simplified mesh with fixed material. I don’t seem to have control over the material it generates.

Even if I can changed the material of HLOD, I won’t be able to distinguish windows from walls in the merged mesh.

In the City Sample, their solution is to always keep lights on even during the day, and during the day, it’s always sunset time. I have dynamic day cycle which can bring the middle of the day, when keeping lights on looks weird.

Any suggestions?