In LARGE Scrum, you must add two supplementary roles (Company ScrumMaster and Company Product Owner):

She is responsible for the Return on Investment of the overall project. She works with the Product Owner Team on the prioritisation of the Backlog Items. She maintains the relationship with the Customer and all other stakeholders. She knows her product by heart, but does not interfere in implementation details. By facilitating the ideas of the Product Owner Team, she drives innovation without having to issue instructions.