We're running our own Exchange server and are now trying to set up different emails for different domains. I'm not even sure if it is possible to do what I want to do but here goes:

I have five different web domains, each with its own email and each domain may have multiple users (e.g., pete@domain1.com, joe@domain1.com, mary@domain2.com, pete@domain2.com).

I want to be able to log into Outlook from my desktop and set it up so through one login, I can see all the emails, separated by domain. I probably can do this simply by setting a rule. But if I reply, I want the default email to be the one that the email came in to (e.g., if the mail was sent to pete@domain1.com, the "from" field in my response will also be pete@domain1.com).

If I'm creating a totally new email, I want to be able to select the account that goes into the "from" field.

Similarly, I'd like to be able to see all the accounts if I log in through OWA, and if it works exactly the same as described above, that'd be great.

Any input will be appreciated.

Thanks,
Bob