Moving to other Domain.

hi,

There's a company that has two parts or sites, they work at the same building but have different domain names, different UPN's, different e-mail addresses. In the past I did create a trust between them and it works fine.

Now, they want to merge both companies into one that will have a new Domain name and so we will have new UPN's and e-mail.

The issue is about the e-mail. Can I pass all e-mail to pst's and then connect it to the new e-mail account? How am I going to make a kind of link between the new e-mail and the old one, to make possible that all e-mail sent to the old address goes to the new one? is it easier just to advise everyone that the e-mail has changed?

I'll use ADMT to make the migration of users from one domain to another.
Thanks.