Elections Code § 6765
ARTICLE 4. Qualification of Group of Candidates for National Convention Delegate Portion of Primary Ballot
Each group of candidates for delegate that intends to pledge itself to the candidacy of a particular candidate for presidential nominee shall have the endorsement of the candidate for presidential nominee for whom the members of the group have filed a preference. The endorsement of the candidate for presidential nominee shall be filed with the Secretary of State before the circulation of any nomination papers of a group of candidates pledged to the support of her or his candidacy as presidential nominee.