Self Service Registration of a contact associated to an ERP Account instead of CX Service Account

Summary:

The classic self-service registration of a DCS user allows associating an Account Key tagged to a CX Fusion Service Account (PARTY in TCA terms). However, what happens if our customer has 1 Party to multiple billing Accounts structure being maintained in ERP (which also shares the TCA)? At an ERP level, there is a provision to associate contacts at Billing Account level instead of a Party level. I'm curious to understand if those contacts can access Digital Customer Service and also see the associated Service Request, Registered Products (Installed Base Assets), Service Work Orders and Site Visits, as with Redwood,