bysort descending

Dear users,

I am trying to use the "gsort -" command to sort observations in descending order. The problem is that I need to order observations within sub-groups, and the "gsort" command does not seem to support the "by:[...] option. Also, the command "sort" does support the "by:[...]" option, but only sorts in ascending order. Any help on how to solve this?

Many thanks in advance.