More Than One Garbage Matte on a Clip

I am using PE 14 and using the garbage matte effect to change exposures in interior window clips.  The general process is to underexpose one clip, allowing a good exposure of the window, then apply a matte to get that exposure on the "good" clip.  This works well when I have only one window to worry about.  I cannot achieve this with more than one window and multiple mattes.

My question, is it possible to use more than one matte on a clip?  I also tried stacking more than two videos, each with its own matte, but that did not seem to work either.

The images below show what I am trying to do.  This is kind of a worst case scenario - I am using these for this for testing purposes. The initial image shows the "bad" windows.  The second image show the improved window (left) with a matte.  But I could not get it to work for the second window - using two mattes on the same clip.

In Premiere Pro, is this possible, using the new layering/matte method?

Thanks