Is there such a mail server?

Question

Mail server

Tell me if there is a mail server in nature with the following requirements:
The user sends a letter from his mailbox, the letter is queued for sending but is not sent. A specially appointed person from his account looks through what is in the queue for sending (if necessary, reads the letter / attachment) and either allows the letter to be sent or not. Ideally, you can choose which users to control and which not.
It is desirable to have access to reading / sending letters from the web muzzle.
For very smart fans to be smart: It
will be used within the framework of one enterprise, it is necessary to maintain trade secrets, etc. All legal issues in this case have been resolved and are not discussed here, they are simply interested in the availability of a product with such capabilities.

Answer 1

Exchange Server had a litigation hold feature (if memory serves). Similarly, the scenario you describe could be configured. Those. the decision on the further fate of the letter is made by a third party. Even the setting was whether to notify the user that the letter was rejected or just send an error about the impossibility of delivery ..