Question about LOD for sections of a map and doing light / precomputed visibility

Right now I have a modular set up for my map. Lots of stuff in view at the same time so to lower draw calls i am creating large merged versions with simplygon with much less polys… What i do is make that low res model appear a certain distance… and the couple of hundred models that were the modular disappear at a certain distance. Right now i use level streaming to create a modular version of an area… and a low poly version of the entire area in another map… They both overlap position wise. So…

Problem number 1.

Level A modular version overlaps Level B low res 1 draw call version… so lighting calculates together so it screws up with shadows on stuff that shouldnt have shadows… because it considers them in the same part of the light. I got around this by building both versions of the level seperately.

Problem number 2.

After i build both versions of lighting and it looks ok, i still have to deal with precomputed visbility… If i build precomputed visiblity with them together… some geometry from the low res map will block out view of the modular version of the map so certain props will disappear unexpectedly.

If i do precomputed visiblity seperately with the other areas of the map envolved… with 2 seperate builds… that doesnt work either. My project is vr and it has a solid 90 fps … if i can use precomputed visiblity… which of course right now… i cant find a way to make that work…

So I guess my question would be to anyone… whats a good way to handle all of this? I mean lighting is acceptable for me the way i do it, but that doesnt help precomputed visiblity.