SBS2003 - 4 companies sharing one server - can they SBS2003 Exchange host email for ea. seperate company?

I have seen other answers in here for creating 'virtual domains' and forwarding email from multiple domains to one domain... I think my question is a little different..but maybe not..

There is a mom & pop organization that has four companies all sitting in the same building..
They are part of one domain currently Company1.local for example.. and they all connect up to a SBS2003 Standard server.

User1 works for

User2 works for

User3 for

Currently their email is hosted with an outside vendor.
I am wondering if I can move their email in-house....and have each of them receive email specific to their company, and send specific to their company.

I don't need User1 in Company1 to send or receive mail for other companies..just the company they work for.

Next question: What about utilizing group calendars, contacts amongst all those users even though they belong to different companies? still possible..or not so much?

Thx in advance,


Who is Participating?
Jeffrey Kane - TechSoEasyPrincipal ConsultantCommented:
Actually your problem is not unusual and is quite easy to accomplish.  I have a similar situation, although reversed perhaps, in that I have 4 different companies and just me... so I send and receive mail from any one of those .coms.

What you are referring to is called "Shared Hosting" for Exchange.  Adding additional TLD's that can be assigned to specific OU's is the way to go.  This will not affect any internal email or calendaring, etc... because they don't actually belong to different companies... you are merely creating "identities" for your users.

Here's a great tutorial and how-to on the subject:

Good Luck!


pdxsrwAuthor Commented:
Thanks for the resource Jeff

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