Using the API: Get customers

/rest/servicedeskapi/servicedesk/{serviceDeskId}/customer

When I set the Customer sharing option in My Service project -> Project settings -> Customer permissions to ** the option "Customers can search for other customers within their organizations, or manually enter the email address of other customers within their project" I would expect customers to be able to query other customers with full email match through this API that are not part of the same organization.