When a private channel is created the system creates groups <Team name> - <Private Channel> [Members, Owners, Visitors]. I have a use case to use these groups for some permissions to a different document library but when I try to use them the system states "Group not found". Is there some sort of filtering that is going on or is that not possible? The groups appear to be standard Sharepoint groups but obviously not. I have tried assigning rights using powershell (Set-PnPFolderPermissions) - but no luck - any ideas would be welcomed.