We have two locations each with a Zimbra server. Site A is running the latest ZCS NE and has plenty of extra licenses. We are hosting email on this server for some of our customers. Site B server is running the open source edition and hosting our internal email. We would like to get on network edition but are too small to justify purchasing a separate block of licenses for that server. We could migrate to the hosting server but don't want to be in a position that anything taking out our customers email at Site A would also take out ours and make it more difficult to contact us.
Is it possible to do a multi-server setup that would keep our email on a box at Site B but still make use of the additional licenses installed on the server at Site A (the two locations are on site to site vpn)? If so could someone give me a brief big picture overview of how such a setup would work? I've looked over the multi-site install doc but still not clear if and how we can achieve the above.