The trick is to name the texture or color with the name of object part.
e.g. The 4 boxes from window frame must have the texture name "frame" or whatever and so on.
I do this usually in AOI to modify all in one step but I think is possible too in SH3D but in multiple steps.
So, You have 2 options:
1. Try to do it Your self (I seen Your work in Gallery and I think You can do it) or
2. Put the obj and mtl file somewhere to be downloaded for modification.