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

He is responsible for setting up the necessary structure for implementing Scrum on an enterprise level. He organises and maintains the Product Owner Team, Product Owner Daily Scrums, the Company ScrumBoard, the Scrum of Scrums. He works together with the Product Owner Team to remove impediments on an enterprise level, to track impediments and to ensure that the productivity of the Product Owner Team increases Sprint by Sprint. Additionally, he performs all activities of a ScrumMaster for the Team cluster.