Scaled Scrum
—Craig Larman & Bas Vodde
—scrum.org
—The Definitive Guide to Scrum at Scale
To scale Scrum, you need a single Product Owner with multiple Teams. Working as a single Product Owner requires rules beyond the scope of the Scrum as written. If you have several fully independent product owners, prioritizing the whole Product Backlog can become unmanageable.
Might be interesting