You can now federate multiple parent domains with a single Access Manager cluster. This means that if the enterprise has users in multiple domains, a single Access Manager cluster can handle the single sign-on requests for all the users for Office 365 services.
For example, if users are across two domains: user1@namtest.com and user2@namnetiq.in. When user1@namtest.com and user2@namnetiq.in access Office 365 services, the same Access Manager identity provider automatically forms the response with the corresponding Issuer URI and sends it to corresponding domains configured in the Office 365 service.