When I look at the groups on the left side -- mine are all alphabetized with the groups starting with a number floating to the top.
It seemed like a good idea that we keep what we think will be our most often used groups at the top of the list.
Unfortunately I don't see a way to segregate groups into lists. It would be nice to maybe put in categories but SC doesn't seem to allow it so I figured alphabetical sorting was the next best solution.