Problem Definition

JSM Admins would like a way to define which Customer Portals a Customer Organization has access to.

Suggested Solution

Provide a way to filter which Project Portals & Help Centers are accessible to a given Customer Organization.
i.e. such that a JSM Admin could make it so that a given Customer Organization only sees the Portals & Help Centers they should have access to.

Workaround

At this time, there is no known workaround.
If one is found, it will be written here.

Note that this is different from just Restricting the Customer Permissions, and not adding the Customer Organization to the Project's Customer page.
In that, Admins would like to still add these Customers to their Project's Customer pages. They just don't want the Portals/Help Centers visible for specific Customer Organizations even if those Customers can raise Requests in other ways (such as through Email).