Multi tenant user control

Hi DennisSchlein ,

You can use Use Microsoft Entra B2B with Conditional Access.

Microsoft Entra B2B (Business-to-Business) lets you invite external users securely and control access with Conditional Access Policies (e.g., MFA, compliant devices).

Benefits:
1.Control how external guests authenticate.

2.Limit access to specific apps or reports.

3. Apply session limits or restrictions (like download prevention in Power BI).
Refer below for more details-
https://learn.microsoft.com/en-us/entra/external-id/authentication-conditional-access#assigning-conditional-access-policies-to-external-user-types

https://learn.microsoft.com/en-us/entra/external-id/tenant-configurations

Hope this helps!
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Thankk You!