Hi
Yes, Check out the possibilities.🙂
For maximum simplicity VP can make at most a 5 x 5 grid using the split screen effect but it would require you to use 25 tracks, one for each student. The upside here is that you would have full control of which person appears in which part of the grid and you can easily swap them about. The downside is that depending on your PC and the size of the clips, 25 tracks is a pretty hefty load for VP to run without any glitches. More students than this this and you would need to use the ideas set out in the stickies where the number of tracks is greatly reduced using exported sequences. Swapping, as Borate mentions would be pretty complicated.
As far as swapping the boxes around using the basic VP split screen setup, things would be much easier. The split screen is added to each of the 25 tracks and the clips assigned to their respective grid box. At some point in the timeline when you want to swap some or all the boxes, split all the tracks. Reassign the positions for the right hand portion of each track. The left hand section will retain their original positions. Repeat the process further along the timeline to make another change and so on.
Nat