Here is a basic building for your games and animations.
The UV is overlapping basically if you change a texture all of the objects with the same material should change.
Texture are:wall (normal map only)windowswoodsground
OBJ (OBJ, filesize: 1.06 MB), FBX (Autodesk FBX, filesize: 12.6 MB), TEXTURES (Textures, filesize: 6.22 MB)