Parent and Child Customer Fields, Core document emailing & B2B Portal functions

I suddenly see that the Customer record has a Parent field, and a side-bar tab for Child Accounts. There is no mention of this in the August 2025 release, nor in the documentation (screen shots do not show these new fields nor discuss their functions).

Am hoping that we can set A/P, C-level contacts into the Parent, and then their Child entities can have site-specific contacts such as facilities managers. 

I tested an account in Core this way, but the Parent contacts do not get emailed for invoices and such, only the Child company contacts. So this is a feature request that emailing sales documents and such to Child contacts would also add Parent contacts to the email (when such contacts are checked-Y for Include in Emails). Not having to enter and maintain A/P and Exec contacts in EACH child record would greatly streamline our contact entry & management, plus deduping for email campaign exports etc.

Additionally, for B2B Portal functionality with Parent/Child, a contact with Parent login should be able to see their Child accounts purchase history and submit orders for distinct Child entities. The contacts at the Child account should NOT be able to see other sister entities nor the Parent entity. 

Then this also brings me to another feature request recently submitted, the ability for a B2B Portal user to toggle billing and shipping addresses that are listed under their customer record. In the case of a Parent contact, they should be able to toggle the Child account to be billed and for the addresses in the Child and the Parent to be selectable from a Parent user login (such as Bill-to the HQ billing of Parent and ship-to Shipping address #3 of Child). Currently, B2B Portal chooses one address for shipping and one for billing, and any changes requires a manual re-key by the user.