Mesh to Substance painter Scale/repeating tiles issue when painting I have tried to make a large building for UE4. It's going to have a brick wall that I will customize in SP or some kind of 3d painting software. 

My issue is when I try to paint it. It repeats the UVs, no matter what I try. I tried to make the building modular, tried scaling it to the right size in the UV editor (export does not work correctly in any of my 3d paint softwares when UV's are scaled outside the image texture), I tried to use mapping node to scale the image texture down, but it will not export as shown in Blender, and a lot more tries and errors.

Are there any tips for making large buildings and texturing for export to Unreal?

I really don't want to downscale textures outside Blender and re-import.
The trick is when you are in the UV editing panel to select the individual faces and apply the the texture needed to each one. So if on the left hand side of your image you want the graffiti, you select that face and assign the image with graffiti to it. You would then select the remaining face/faces and just apply the brick texture without the graffiti.