Internal security check of outgoing emailings

Our services are used for collection of payments from defaulter. 1. Since we use emails to correspondence with our Principle like Banks, we want to make sure that the emails/information send to the clients don't go straight to them, but it is received at one point at the internal server. The admin scrutinises all the outgoing mails. Then he checks with the Chief Officer and on his approval the mail is send. 2. We use Outlook Express 3. Messages received has to be acknowledge when read at our end, (this acknowledgement doesn't need scrutiny) so the client is aware we have received the same and at what time. 4. The scrutiny of the mails will be handled by three Admin persons. One by a main person (First Admin) if he is not available then the next person (Second level admin) and if this person is also not available then the Third Admin. 5. These mails should have time delay of 5 minutes (or programmable as per ours time-delay requirement) for the above item 4 requirement. For e.g. if we have 5 or more outgoing mails send from one or more computer terminals then the mails will be in queue at our internal server(waiting for the mail to be read and scrutinised) it shouldn't send alert message to the next level admin if he is IN and at his computer, only if he is not in and therefore it can't be read only then should it send an alert message for the next level admin to take action. 6. These mails ones it is read and found everything is okay then it is send to the clients. 7. As for the Operator the mail is gone/send from his terminal when he gives the send command, but he is not aware that his mail is blocked at the internal server level for security reason.