Adding Office365 Shared Mailboxes to CAS
If customer wants to add O365 Sheard Mailboxes to CAS, then best way to do it is to configure group filter.
Shared mailboxes do not show up in the licensing screen or the policy screen. Regardless, we will still scan the emails sent to shared mailboxes.
If you need to add a shared mailbox to a specific policy you can use the all users and groups scope.
Alternatively, you can add the shared mailboxes to a mail-enabled group and add that group to a policy.