California Code, Public Utilities Code - PUC § 1703

All matters upon which complaint may be founded may be joined in one hearing, and no motion shall be entertained against a complaint for misjoinder of causes of action or grievances or misjoinder or nonjoinder of parties. In any review by the courts of orders or decisions of the commission the same rule shall apply with regard to the joinder of causes and parties as herein provided. The commission shall not be required to dismiss any complaint because of the absence of direct damage to the complainant.