I have an O365 group used for a project. It has a few owners and a couple dozen members. They use Files in SharePoint. Fine.
On a different SharePoint site, I want to give updates to the whole company, so everyone is Visitor. In the SharePoint Site Members group I only want the owners of the above O365 group. I don't want to list them by name. If I use the group name, it grants access to all members of the group, I only want to give access to the owners.