would this way work for you? You have your files somewhere, on your ownCloud or on an external Storage. For the sake of argument lets just say you have 2 files uploaded on your ownCloud in your administrator directory. So if you log in as administrator you see both files. Now you want to give one of the files to all your users, so you share the file to the group "users". now the users can see the file. the one you did not shared, only you can see.