Picture in Picture (PiP) Zoom

I have a basic understanding of creating a picture within a picture. Before buying Preniere Elements, I want to determine if what I need to do is possible. There will be a video of a perrson speaking. There will also be PwrPt slide showing graphics. I would like to expand the picture with the slide to permit viewers to see details, then shrink that window back so the presenter is visible with a smaller size picture of the slide. Zooming within the small winddow is not what I need to do.  Preferably, the zoom of the window size is a smooth transition rather than a step. I assume that I could create multiple copies of the slide file and place each in a different size window, but that seems pretty labor intense and would be a step function instead of smooth expansion or contraction transitions.