I have a highly-related question...

Every user on the system is in his own group, so files for user "bob" are 
created by default with owner "bob" and group "bob".  Most users are also 
in a group called "staff".  I want to make a shared space for the staff 
group where every file and subdirectory created within our staff directory 
always has the group "staff" (recursively for the whole tree).  This will 
be our shared space.  How can I do that?

The system where I'm most interested in doing this now is a CentOS system, 
but I want to be able to do it on Ubuntu or any other Linux system.

By the way, I really don't like this new scheme where every user has his 
own group.  I know that it helps to keep things private, but I'm working 
on a system where I want more sharing and less privacy.  I suppose it 
protects us a little bit from rare mistakes, but it gets in the way all 
the time.  The people managing the system think we can have this shared 
space, as described above, but so far we don't have it.

Mike