limit the message size for a Distribution list

[leo de punk]

hi all,
I am so new to Zimbra and struggling to manage my distribution list according to my requirements. I need to send messages to a distribution list with a limited size. (less than 2 Mb) If message size is greater than 2Mb it needs to be rejected. because we have more than 2000 mailboxes and we have a one distribution list called everyone@ourdomain.com. only certain users can send mails to everyone@ourdomain.com and those mails need to be less than 2mb. If we allow them to send with a maximum message size which defined in the global settings we would have to face a big bandwidth issue. therefore we need to have a different setting to set the message size for distribution lists.
I tried to filter the outgoing messages by using zmmailbox command. But it doesn't work.

please give me your suggestions to solve this.


thanks in advance
regards
leo