Multiple Exchange Accounts, Multiple Domains, Same Server...Issues

I have both an Exchange 2010 server and Exchange 2013 server that I host for multiple clients across multiple businesses. I have a single client that has 3 domains to which they would like to have full e-mail control over. Here is what I mean.

Quick explanation of how we do it now:
We have a single Exchange account and then 2 POP3 accounts which deliver to the Exchange OST, we use Search folders to separate the mail into dedicated "Inboxes", when you reply it auto selects the account that it was sent to and all is well. HOWEVER, when you introduce smartphones and tablets, the POP3 accounts don't sync, thus all mail sent from those devices is only on the phone. Also, mail deleted on the phone is not deleted on the laptop/tablet etc.

OK moving on...

Client A owns and operates 3 different businesses to which they want all e-mail contact to be completely separate from each other. They must be able to send and receive messages to each domain.

You get the picture. So if a message goes to, he needs to be able to reply as

Then, due to the large number of e-mails received, they would like a Unified Inbox, which in all of my searching, I have not come up with a solution to show all Inboxes in a single Inbox. My only solution so far was a VB script that uses a search command to search multiple Exchange stores. All other search features only search within a single Exchange datastore and will not search the others.

Finally, all of these accounts (in theory) would be placed on the same Exchange box. I have no desire to build multiple Exchange boxes.

What I am finding is even trying to add multiple exchange accounts to a single Outlook profile I get an error because of dual authentication to the same server with different usernames and passwords.

Any thoughts? Suggestions? Need more info?
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Simon Butler (Sembee)Connect With a Mentor ConsultantCommented:
What the client demands and what is possible are not always the same thing.
I don't think what you want to do is possible - if you want separate address books then you need to have separate accounts in Outlook.


First of all I think that you have two separate questions here:

- the first is regarding POP3 and mobile e-mail synchronization
- the second is regarding "Unified Inbox"

I am letting you know this because in my opinion you should have opened two separate questions.

My answer is regarding your second question and the suggestion is to use outlook rules, like here:
Simon Butler (Sembee)ConsultantCommented:
You have overcomplicated this.
Decide on the primary account. Give Full Mailbox and Send As permissions to the other two accounts to the primary account. That will allow you to have one set of credentials to access all mailboxes.

Have three mailboxes and add them in to Outlook as additional accounts. While there will be three inboxes, they will get notifications across all three.
If you want to send email as all three addresses then with the current technologies a unified inbox isn't possible.

The other option is to use a third party tool called Choose From from

iowasolutionsAuthor Commented:
Sembee2  Thank you for the information - that works except the client demands to see all of the inboxes in one place like they do on their iphone.  That is only thing we are missing in  setting up like this - except the Address Book.

The Address Books Merges all people for three companies.  They would prefer the companyA only see their people, etc.

When the second account in under a different domain the address book doesn't cross over in multi-tenant mode when using address book policies.
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