[exim] help in setting up filters

Hi,

I am a newbie at administering our company's mail server which is hosted at
GoDaddy. The cPanel says we're running Exim on a CentOS server.

My problem is this:

1. My boss wants to set up our email system such that all outgoing
emails coming from our agents to our clients will pass through a
"moderation queue" before being actually sent to the client.
2. The "moderator" should be able read, review, edit, and send the
messages from the "moderation queue" to the client.
3. The client should see the email as coming from the original sender
(the agent) NOT the moderator.

I have been reading the docs from Exim.org and searched for "Exim filters
tutorial" from Google but still I can't make it do what I want. I am a
developer with no experience with administering mail servers.

Right now, I'm thinking of using a filter that will forward all outgoing
emails to a moderator account instead of the client's account. After the
moderator is finished editing, he can then send it to the client but the
"From:" header should still read as the original sender.

Is my plan even possible in Exim? Are there other better ways?

Any help will be greatly appreciated!

Noel Martin L.