California Code, Elections Code - ELEC § 16642

The judges designated by the order to hear the contest, including the judge to whom the contest was originally assigned, shall convene upon notice from the judge to whom the contest was originally assigned, and agree upon the precincts which each one of them, sitting separately, will recount.  Thereupon the recount shall so proceed that each judge, sitting separately, shall respectively determine the recount in those precincts which have been assigned to him or her, so that the ballots opened before one judge need not be opened before another judge or department.