Defrag more than 1 drive?

I know Defraggler will only defrag 1 drive at a time, but why can't I select 4 or 5 drives, and then press Defrag so they are defragged one after another with the GUI?

TIA

Groucho2

I think it's a good suggestion if the other drive(s) could be queued, however depending upon the size of the drives you could be looking at a seriously long time to complete the defrag.