Localized transformations - Slide

Hello everyone,
I have to perform an apparently easy task that is proving a bit harder than I thought.
I have to edit a news cover - I need the general layout to stay the same, while the pictures cycle with the basic FCPX slide movement effect.
How do I apply this transformation to a smaller area, without affecting the whole layout?

Imagine I were using the attached image - how do I get the monkey picture, and only the monkey picture, to slide into a different image?

Thanks for your help!

You need two graphics. The newspaper layout with a hole cut in it on the top layer and the sliding images on the layer underneath.

thanks!