I don't think there's a specific feature to reorder the contents of the Authors column. I'm wondering why you would want to do that anyway, the order they're in often has relevance… e.g. institutional seniority.
This works for me:
- F2 to open the Authors cell for editing in the Book list;
- then Cut and Paste around the '&' character(s) within the cell;
- the Author sort column will take care of itself.
BR