Populating the "Import Package" Menu

I work in an educational institution where we use several common Unity Asset Store packages in curriculum. In previous versions of the editor (e.g. 2018.2.5), we could copy .unitypackage files into C:\Program Files\Unity\Editor\Standard Assets\ and they would automatically show up in the Assets > Import Package menu.

In the latest version of Unity (2019.2.1), this no longer seems to work. Is there a way to populate the "Import Package" menu with commonly used packages for all users on a workstation? Or do users have to now choose the "Custom Package..." option and navigate to the .unitypackage file on disk?