I would like to grant external business partner users access to my Power BI tenant using the Power BI Service so they have access to our reports just like my employees. I need to secure access using their User ID and RLS (likely using SQL Server 2016 RLS). I have a hundred or so reports to share with thousands of extneral business partners. I don't want to add them to my Office 365 tenant since they already have their own O365 tenant and most of them already have a license in their tenant to Power BI Pro, so I we don't want to purchase the same software twice. All these users already authenticate using SSO to more than dozen applications that we provide, so I would like to use the same credentials they already use. I've done a lot of reading on this site and have yet to find an approach that would meet our needs.
I have a few ideas:
1) If I could do forms based authentication to the Power BI Service and if Microsoft could verify that their external email address is already licensed for Power BI Pro, then I would be good.
2) If I could grant guess/external access to my Power BI Service tenant by providing an external AAD email addresses that would link to their O365 Power BI Pro license, then I would be good.
Any thoughts? I can't imagine I'm the only business that wants to provide external business partners access to their Power BI tenant.
Thanks