Contacts Discovery

Greetings All, I’m new to MIAB and I’m having a pleasant experience with it so far. Things have been going very smoothly. However I am new and unfamiliar with a few things related to contacts sync and not sure whether this question has been asked before or not. I tried searching the forum but haven’t found what I’m looking for.

I have multiple domain names, each for a single organisation. I want all user (email addresses) to be visible / discoverable for all other users of the domain. I am not talking about Exchange/Activesync here. Correct me if I am wrong, activesync cardav etc will sync YOUR contacts, so if you don’t have any contacts, it has nothing to sync.

Here’s the scenario. A company recently asked me to set up their mail server. Which I did and everything is working. The company has been using gmail / private addresses for all communications. Now that they have address, they want suggestions to be listed when they are sending emails. So for this, it would be great if all addresses of are listed in contacts of each user. So if 1@conpany com is composing an email, other 2-100@company com address should be listed in their contacts so that it is easier for them to send/receive emails on new email company accounts.

How can I achieve that?