A few days ago, we deployed a new version of the unrestricted guest account function.
The new version allows a very granular permission granting/denial to your Guests (business partner, VA, accountant, …)
You can restrict access to marketplaces and within marketplaces, you can choose which of the (currently) 79 SellerLegend functions you want to restrict/permit.
The Knowledgebase article is here.