Ok - I'll wait a long long time untill I put any bus in the tgd
I mostly only integrate objects or object groups (busstop e.g. is 3 seperate parts because of the glass parts)
so I almost never run into problems because not having overlapping features. It's only a tool for me to have high working speed while experimenting with objects and get all the texture and other settings into the scene later.
When I tried the integration of the cracks in the street as tgc as I also had no problems. But that was in the beginning. Now I have app. 80 objects and 81 populations in the scene. It's a complicated work but when it's finished I can just switch between the cameras (if needed activate or deactivate not needed pops or objects). At the moment I have big advantages with this strategy while I'm rendering the desert scene from 4 camera perspectives.
Edit 12:44
In this moment I see exactly the problem comming you talked about, Ulco, but also the solution.
The glass shaders of the houses and the busstop could collide with some glass shaders in the big "suburban" tgd.
I better give them unmistakable names to avoid overlapping
