Upper half shows one video track, lower half shows another
The easiest way is to use nested timelines.  Make each source timeline the appropriate size for the half it is on.  Apply the motion within the nested timelines.  Then place the nested timelines on the top and bottom of your final timeline.

I use this technique regularly in both Premiere and After Effects when I need to combine multiple elements into a layer than I then want to manipulate as a whole.  In After Effects, adjustment layers are also an option, but I often need to treat the same sub-asset in different ways in different finished videos (working on lower thirds generally), so the nesting approach makes more sense for me.