We have just installed an environment of Zimbra 8 with approximately 18000 users and 2 LDAP servers, 4 proxy servers and 6 mailbox servers.
Everything seems to be working smoothly although not all users have been migrated in the new environment yet.

We are currently looking for a way to limit the size of the emails received by a distribution list, no matter whether the list is dynamic of static.
Of course Zimbra's deduplication makes things easier as far as disk consumption is concerned, but we also want to keep the mailbox quotas to a minimum, as well as bandwidth consumption.

We noticed that with the parameter amavisMessageSizeLimit you can limit the size of emails received by a user account, but there is nothing similar to the LDAP attributes of a distribution list.
We tried to add the class amavisAccount to the LDAP schema of the distribution list with no luck. The class is added but it is not activated when the email is received.

Does anyone know of a way to modify the LDAP so that the amavisMessageSizeLimit is triggered when a list receives an email?
If not, can anyone suggest of a way (e.g. postfix configuration) with which the size of the emails received by a distribution list is limited?