Export a project including linked files

I have a city street project that consists in:

  • Several .blend files, each one containing 1 building
  • 1 Master .blend, providing the overall scene, the right positioning of the buildings (each single building .blend is linked) and complementary elements

Now, I have to export the whole project to a 3rd party by using an exchange format (.obj or whatever). No problem for the building files, I can export separately each of them. But for the Main scene… if I export it in .obj I’ll loose the correct positioning of the buildings, so I would be obliged to import everything in the new system and to re-position each single building.
Is there a smart way to export all the project by preserving the right positioning of the buildings?

(no way to include all the buildings in the Master file. I would have a single file easy to export but its dimension would explode)