Mail + quota

[Kiss Gábor <kissg dataminer hu>]

Dear All,

I would like to set a quota for a group. I have created the users, all in
the same group. I see the users (po boxes) in the directory /var/spool/mail.
My question is, why has the po boxes "mail" group without my "group". How
can I set the quota of my "group" for the e-mails.
Backgroud: we have users, their have place for e-mails and their have limit
for all and not per user.

Thank you
Gábor