Hello,
you can create an usergroup object with the defined access to the folder.
This usergroup is only available in the Automic System / clients you want to use this. The usergroup is not available in the other systems / client. So if the user is assigned to the usergroup you control the access to the folder in other systems / client where the usergroup is not defined the user has not the authorization to access the folder.
We do this in one of my projects and it works
Regards
Thomas