Cal. Unemp. Ins. Code § 1097

The manner of crediting to each employer the employment experience of the group of employers who have appointed an agent pursuant to Section 1096, for the purpose of any classification of employers made pursuant to this division for the determinations of future rates of employers’ contributions, may be prescribed by authorized regulations. Employers who operate or do business in more than one place may, with the approval of the director, appoint a separate agent in each such place.