Update microsoft-sentinel-onboard.md

Author: batamig

unified-secops-platform/microsoft-sentinel-onboard.md

@@ -68,6 +68,8 @@ To onboard and use Microsoft Sentinel in the Defender portal, you must have the
   |**Take investigative actions on incidents** |[Microsoft Sentinel Contributor](/azure/role-based-access-control/built-in-roles#microsoft-sentinel-contributor) or a role with the following actions:</br>- Microsoft.OperationalInsights/workspaces/read</br>- Microsoft.OperationalInsights/workspaces/query/read</br>- Microsoft.SecurityInsights/incidents/read</br>- Microsoft.SecurityInsights/incidents/write</br>- Microsoft.SecurityInsights/incidents/comments/read</br>- Microsoft.SecurityInsights/incidents/comments/write</br>- Microsoft.SecurityInsights/incidents/relations/read</br>- Microsoft.SecurityInsights/incidents/relations/write</br>- Microsoft.SecurityInsights/incidents/tasks/read</br>- Microsoft.SecurityInsights/incidents/tasks/write    |Subscription, resource group, or workspace resource  |
   |**Create a support request** |[Owner](/azure/role-based-access-control/built-in-roles#owner) or </br> [Contributor](/azure/role-based-access-control/built-in-roles#contributor) or </br> [Support request contributor](/azure/role-based-access-control/built-in-roles#support-request-contributor) or  a custom role with Microsoft.Support/*|Subscription  |
 
+  If you're working with multiple tenants, note that [granular delegated admin privileges (GDAP)](/partner-center/gdap-introduction) with [Azure Lighthouse](/azure/sentinel/multiple-tenants-service-providers) isn't supported for Microsoft Sentinel data in the Defender portal. Instead, use [Microsoft Entra B2B authentication](https://learn.microsoft.com/en-us/entra/external-id/what-is-b2b). For more information, see [Set up Microsoft Defender multitenant management](mto-requirements.md#review-the-requirements).
+  
   After you connect Microsoft Sentinel to the Defender portal, your existing Azure role-based access control (RBAC) permissions allow you to work with the Microsoft Sentinel features that you have access to. Continue to manage roles and permissions for your Microsoft Sentinel users from the Azure portal, as any Azure RBAC changes are reflected in the Defender portal. 
 
   For more information, see [Roles and permissions in Microsoft Sentinel](/azure/sentinel/roles) and [Manage access to Microsoft Sentinel data by resource](/azure/sentinel/resource-context-rbac).