Add a common (multi-tenant) Azure AD Identity Provider
An idp that can be used to set up the AAD "common" tenant, which does home realm discovery (customer types in their email address and the real tenant is looked up) to find the actual AAD tenant. This would allow any customer with an AAD account in any AAD tenant (that has not disallowed it to be used with the common tenant) to authenticate.
This is possible through custom policies (see documentation below). We are planning to bring it into built-in policies within the next 6 months.
Victor Carlson commented
How is the status of this feature? When will it be out for preview?