Postfix quota per virtual domain

[Olivier Nicole]

Hello,

I am working on a Postfix email server for virtual domain. I was
requested to implement quota per domain, not per user: the sum of
mailboxes of all the users in the domain must not exceed the quota set
for the domain. 

(All I could find was example where all users of the domain had a same
quota amount, fixed for the domain, but each individual mailbox counts
for its own quota.)

Have you ever seen something like that?

Best regards,

Olivier