Tenant migration

Hello,

We are looking for a way to migrate a part of our users to a new O365 tenant with the least possible downtime.
Currently we have about 250 of the 600 users that we want to migrate to a seperate tenant.
All users will stay in the same domain.

Current situation:

1 tenant
1 domain
AD Connect
S4B Enterprise
ADFS (will be replaced by SSSO on new tenant)

To be migrated:
Mailboxes
Onedrive
Teams (incl. conversations)
Sharepoint
Resources (meeting rooms)
Calendars
S4B

The to be migrated users have a different UPN and email address.
We could setup a second AD Connect and filter on UPN, but I'm wondering if all the above can be done with no downtime and if this would cause issues later on.
it infraAsked:
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Adam BrownSenior Systems AdminCommented:
Tenant to Tenant migration cannot be done without downtime unless you are changing the email address and upn for the users when they get migrated.

AD Connect, however, cannot be configured to connect to multiple tenants using the same active directory (unless things have changed). To accomplish that you need to use Microsoft Identity Manager, which is a much more difficult sync app.

I would recommend using a third party migration tool like migrationwiz to do this, since it helps a lot on tenant to tenant stuff. Regardless, the migrated users will need to be cloud-based users in the new tenant because you won't be able to sync to two tenants from the same AD (Again, unless you use MIM.)

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it infraAuthor Commented:
Thanks for your answer!
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