Partial Migration from On-Premises Exchange 2007 to Office 365 Exchange Online

We are currently in the planning stages of migrating a client's Exchange 2007 database to Office 365 Exchange online. The part of the project that we're not sure about is how to only move one database and leave the other in production.

The situation is such that we have two organizations sharing one Exchange server. Both have their own Exchange db, but share a single local domain. Each does have it's own www domain, so separating them isn't an issue.

All of the documentation we've found so far assumes that only one organization is being migrated and then the on-premises Exchange server will be decommissioned. In our case, we have two organizations, one will continue using the on-premises Exchange server while the other will migrate to Office 365 Exchange Online.

Has anyone had any experience with this or can someone point us in the right direction?
btnyAsked:
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Vasil Michev (MVP)Commented:
Staged migration should be the way to go:

http://help.outlook.com/en-us/140/Ff959224.aspx

You can migrate only a subset of the users, even from multiple domains, as long as it is the same AD forest. It is NOT necessary to decommission the Exchange server after the migration, it's only a recommendation (Outlook will always hit the SCP first and if you have local mailbox still active it will fail to connect to EO. There are workaround for this ofc, such as editing the registry: http://support.microsoft.com/kb/2212902)

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Jian An LimSolutions ArchitectCommented:
you can go for stage migration or hybrid migration

depends on the size of the oganisation. I will recommend hybrid as it offer the maximum compatibility between cloud and your local environment.
This also give you the ability to quickily move people in/out of the organisation.

http://technet.microsoft.com/en-us/library/hh852414.aspx

Again, really depends on your case and see which is prefer method.
Sam RavenscroftIT ConsultantCommented:
The links referenced in this article is outdated and no longer work.  Can you please post updated links?
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