Migration Dilema 5.5 to 2000

[PerseusMi]

Here's the dilema. I need to migrate from Exchange 5.5 to 2000, migrate from NT4.0 to Win2000 & as an added bonus migrate users to a new domain (xxx.com to yyy.com ). Also I would still need to be able to recieve email from xxx.com on my Exchange that would be in yyy.com.


Current Config Desired Outcome
-------------- ---------------
xxx.com --------> yyy.com
Exchange 5.5 ---> Exchange 2000
NT 4.0 -----------> Win2000

Would I have to add my New WIN2000 into the xxx.com domain, install Exchange 2000 and replicate those users from the xxx.com and their mailboxes with AD with 2000? Then bring to life another 2000 box in the yyy.com domain replicate those accounts over to the yyy.com and then remove my servers in the xxx.com? What's the best way to make that happen? Any suggestions?

Thanks