Is it possble to implement, within zimbra, a per-user daily message throttle/rate limit?

In order to help prevent spam from compromised accounts, i'd like to place a per day mesage count limit per account. Something that would warn an administrator once an account hit threshold A, and start delaying, or outright stopping, delivery once the account hit threshold B.

This would give an administrator time to stop a spam/phish outbreak from a compromised account before it got out of hand.