you should be able to use a UI Post Load event script on the purchase order printing panels (regular and quick print). in the script you will need to check if the current user is or is not a member of a role that you can create to either exclude or include users who can use paperless (or hard code the user, bad practice in my humble opinion). depending on the result of checking the role, you would then set the value of the paperless office output to the equivalent of Print All and then lock the field. I believe you might be able to find some similar examples on the forum.