California Code, Penal Code - PEN § 784.8

If more than one felony violation of subdivision (d) or (e) of Section 368 occurs in more than one jurisdictional territory, the jurisdiction of any of those offenses, and for any offenses properly joinable with that offense, is in any jurisdiction where at least one of the offenses occurred, subject to a hearing, pursuant to Section 954, within the jurisdiction of the proposed trial.  At the hearing held pursuant to Section 954, the prosecution shall present written evidence that all district attorneys in counties with jurisdiction of the offenses agree to the venue.  Charged offenses from any jurisdiction where there is not a written agreement from the district attorney shall be returned to that jurisdiction.  In determining whether all counts in the complaint should be joined in one county for prosecution, the court shall consider the location and complexity of the likely evidence, where the majority of the offenses occurred, the rights of the defendant and the people, and the convenience of, or hardship to, the victim or victims and witnesses.