California Code, Code of Civil Procedure - CCP § 378

(1) They assert any right to relief jointly, severally, or in the alternative, in respect of or arising out of the same transaction, occurrence, or series of transactions or occurrences and if any question of law or fact common to all these persons will arise in the action; or

(2) They have a claim, right, or interest adverse to the defendant in the property or controversy which is the subject of the action.