I'm looking forward to migrate an Exchange 5.5 installation to ZCS.

My main regard is that the exchange has 11k+ mailboxes, all of them configured with an "Alternate Recipient" and "Deliver messages to both recipient and Alternate recipient" checkbox enabled.
This way, whenever an email arrives to any mailbox, the email is forwarded (and a copy stored in the original mailbox) to a distribution list (there are 7k+ DLs configured).

So, with these said, if I run the Zimbra migration tool, to migrate all the mailboxes & DLs, will this configuration remain in the new Zimbra server? Manually adding forwarding rules for 11k mailboxes is clearly not an option.

Thanks for your support.