Add a Word 2016 startup folder for macros in the registry

I need to set a startup-folder for my macros for Microsoft Word 2016.

I thought that adding a "AltStartup" registry key would work - because it works in excel but it does not seem to work with Word.

The startup-folder should be C:Program Files (x86)Microsoft OfficerootOffice16Startup and it should be a trusted folder so that my users don't receive waings because macros are loaded.

How can I set a registry key so that Office will load my macros on Startup from my directory?