We are migrating several user mailboxes to a new Exchange server due to spinning off a new company. We have setup the Exchange Server (2013) in it's new domain xyz.com.
The new company users have been receiving email for the new domain through our current Exchange Server (2010) which resides on domain abc.com.
We cannot change the MX records for domain xyz.com until we have moved all the users' mailboxes.
How can we forward their emails from our current Exchange server to their new account without having to create contact cards for each user? This will be necessary so that their new mailbox will receive the email until our ISP changes the MX records and unfortunately, they do not complete work orders at a fast rate. It could take a week for them to change the MX.
Any assistance would be of great value.