Image getting progressively covered by foreground objects

I'm trying to put an image in a room window that sits "in the middeground" with the activity behind it being blocked by the image but for it to be covered by the things happening outside of the window, with it eventually being covered over when a piece of wood is put over the window. My understanding is that I cannot assign a mask to a person who is moving or the piece of wood in order to make sure that when those objects are in the same pixel as the image that they cover it in that area.

I've also tried to mask each individual frame but am not at able to limit the mask to the one or two frames that it works in and add another one for the next frame. 

Anyway to make this happen?