Support 3D-tiles 1.1 export - not only the old 1.0 b3dm 3d-tiles standard

For reference, one can choose multiple texture layers to export when exporting Models/static meshes like fbx.
At the moment, when exporting a 3Dtiles tileset, one can only choose a single source-layer. It would be great to extend that multi-texture exports for 3d-tiles as well - and have them referenced in each individual tile material. Thanks!

I assume 3d-tile export is not deterministic enough to “just” export the 3dtiles mesh with texture-1, texture-2, for a given tile to have the same uv-map so that this tile texture-1 and texture-2 do overlay correctly.