How can I align a filmstrip composition to a predefined path?

My question is: How can I align a filmstrip composition to a predefined path?

I have a composition which consists of two movie reels turning, and another one of a filmstrip moving down vertically. My intention is now to align the filmstrip along a predefined path between the two reels, to make it look as if it comes out of one reel and loops into the second reel. The common practice to copy the mask path and paste it into the position properties of the filmstrip composition would not align it along the path, it rather keeps the whole composition steady and moves it from one vertex point to the next.

Thanks in advance for any suggestions.