Something like this?
https://playground.babylonjs.com/#VN9J3X#3
I have a couple other methods that would give you more control but are way way way more complex.
You might want to have separate lines systems for the outline vs the inner details, but yeah its totally doable with some smart modeling and a good setup.
If you wanna go the super nerd route and do a custom shader that identifies all the element by vertex color then scales them on the vertex shader, capture a RTT of the scaled down meshes with their ID color. Then scale them back up keep the ID colors the same capture that RTT, bring over to a postprocess and then do some magic math to cut out the sections of the mask that match the color IDs. You would have to do this at least twice actually, once for the outline of the main building with all its facets scaled and then once for the facet groups of the building scaled locally by their grouping. Combine both those and next onto the shadow projection… sooooooooo basically yeah lets not do that and try to figure out a way to make this more simplistic setup work for you.