We have an old mailserver(mail1) application currently that we plan on replacing with Zimbra in the near future. mail1 has 150 email accounts tied to it, half of those are actual employees the rest are automated accounts.

Is there a way to deploy the new Zimbra server and have it pass addresses it doesn't hold to mail1?

I ask since we are purchasing Zimbra for actual users, which will be 75 licenses. We want to keep the featureless stuff relegated to the old mail1.

So, can we do it?
thanks