Sharing Ad-Hoc Folders

Greetings,

I have been reading some posts in the newsgroups, and also on other
forums, but still haven't quite found what I was looking for.
We need to let our users share folders in Windows Vista, in the same way
they did on Windows XP. The users are Power Users, and apparently only
Administrators can share the folders, without being prompted for elevated
privileges.
I read somewhere
(http://www.tech-faq.com/what-are-sha...missions.shtml) that users
had to be "a member of one of the groups that have rights to share folders on
the computer where the file resides."
Which group is this? Is there a group policy on AD allowing me to enable
this feature for all computers?

Thanks in advance,

Rodrigo Monteiro