I have found an article whilst looking into applying IRM to SharePoint libraries here: https://docs.microsoft.com/en-us/azure/information-protection/office-apps-services-support
Within the article, it states:
Word, PowerPoint, Excel, and PDF documents support this SharePoint IRM protection. By default, the protection is restricted to the person who downloads the document. You can change this default with a configuration option that extends the protection to all users who have access to the document on SharePoint, or to a group that you specify.
However, I cannot seem to find any further documentation on how to configure extending the protection to all users who have access to the document on SharePoint.
Is this only possible by adding all users who have access to to the document on SharePoint in one mail enabled security group and adding that group to the group protection field in the IRM configuration? Or is there another specific configuration like the article linked leads me to believe?