Cal. Civ. Proc. Code § 369.5

(a) A partnership or other unincorporated association, whether organized for profit or not, may sue and be sued in the name it has assumed or by which it is known.

(b) A member of the partnership or other unincorporated association may be joined as a party in an action against the unincorporated association. If service of process is made on the member as an individual, whether or not the member is also served as a person upon whom service is made on behalf of the unincorporated association, a judgment against the member based on the member’s personal liability may be obtained in the action, whether the liability is joint, joint and several, or several.