Referencing Substance scenes and materials

For complex projects it would be a huge time saver to have on master scene and several other ones using it as a reference and save just the modifications, additions and deletions.
Currently I have a rather sophisticated setup for a vehicle with 30 modifications (design variations). I thought I create a base scene primarily holding all the materials for normals, smoothness/roughness, height, opacity, etc. and then create a new Substance scene for every design, load the master scene as a reference into it, and build my color textures and materials. Save it, repeat with all the other designs. If I change something in the master scene the modifications are reflected in the other scenes as well.

Sadly I had to find out that Substance Painter does not support this. Ok, so save some smart materials on disc and do it this way! Oh, Substance Painter does not support loading materials as references (if I update the file on disk all Substance scenes auto-update on load).. :(