Hello,
To impliment your request, it will take some time to set up, but there is no reason why it wouldnt work, I have done something similar before.
I would configure a suedo domain in exchange which has similar naming to the real name e.g. companyname.exchange rather than companyname.com
The exchange setup is then simple
1. You configure the specific users you would like on Exchange (note on the companyname.exchange domain)
2. Have exchange operating as its own email domain (companyname.exchange)
3. Configure the outgoing mail to use a smarthost, the smarthost should be set to your AMS server.
The AMS setup requires a little more time, but still relatively simple.
1. you configure an outgoing static route in AMS for companyname.exchange to route directly to the IP address of your exchange server. This will ensure the emails sent to the exchange server go to the right place and are not lost in DNS issues!
2. you configure each user which you are using on exchange to redirect their email to their exchange email address (e.g.
ian@companyname.com will be redirected to
ian@companyname.exchange), you then also have the option of also delivering to the AMS mailbox if you want the user to have access to both, however this could potentially lead to full mailboxes.
3. you set a content filtering rule for emails received which changes the SENDER header AND FROM header addresses from companyname.exchange to companyname.com on their way through to the outside email system. (Sadly this may be 1 rule per person as I dont think you can replace part of a header, Chris/Rob will correct me if you can)
This third point is to ensure you are still sending emails from the correct domain name.
I hope this helps, and it should work.
Best
Ian