Tracking an external matte

Hi all, I'm hoping you might be able to help. I am trying to fake the lights of a passing village to footage of the dusk skyline shot out of a train window. I can track the stand of trees that I'm using as reference point of the imagined village, and use this to expose an external matte. However, this merely shows the relevant portion of the matte, where I want to be able to move a specific portion of my external matte containing a specific cluster of lights, using the tracking information.

Any help would be greatly appreciated.

Steve