A person who claims or controls an interest in any matter subject to disposition in the proceeding may be joined as a party to the family law case only as provided in this chapter.
For purposes of this rule, a “claimant” is an individual or an entity joined or sought or seeking to be joined as a party to the family law proceeding.
The court may order that a person be joined as a party to the proceeding if the court finds that it would be appropriate to determine the particular issue in the proceeding and that the person to be joined as a party is either indispensable for the court to make an order about that issue or is necessary to the enforcement of any judgment rendered on that issue.
In deciding whether it is appropriate to determine the particular issue in the proceeding, the court must consider its effect upon the proceeding, including:
If the court orders that a person be joined as a party to the proceeding under this rule, the court must direct that a summons be issued on Summons (Joinder) (form FL-375) and that the claimant be served with a copy of Notice of Motion and Declaration for Joinder (form FL-371), the pleading attached thereto, the order of joinder, and the summons. The claimant has 30 days after service to file an appropriate response.
(Subd (e) amended effective January 1, 2017.)
Cal. R. Ct. 5.24