What's planned (ADR-028, item 3)
Bulk role assignment across ad accounts and Pages, and an asset group for one buyer — over the official Marketing API, with the same System User token.
Not in the code yet
This function is a decision on record (ADR-028), but no module exists yet — this text stays a draft until the code ships.
What this won't do
Like every BM-management function: no creating ad accounts, Business Managers or system users, no inviting people, and no Page roles outside the BM.