When using the synchronization portion of QMM to mailbox-enable accounts, a mailbox store is specified. How do you change this option after the users have already been mailbox-enabled? This may be desirable if, for example, you do not want all of the users in the synchronization scope to use the same mailbox store.
This can be achieved through Mailbox Collections. In the properties of a mailbox collection you can specify a mailbox store in which to place mailboxes. Create a mailbox collection containing users that you want in a specific mailbox store, and select that mailbox store in the properties of the collection. When mail synchronization begins, the mailbox will be created in the specified mailbox store.
See Solution SOL15440 - Moving Target Mailboxes in the Middle of Mailbox Sync Job -https://support.quest.com/SUPPORT/index?page=solution&id=SOL15440