Whenever any judge of a separate juvenile court is disabled or disqualified to act in any cause before him or her or is temporarily absent from the county or whenever it would be beneficial to the administration of justice, a judge of the district court may agree to serve as judge of the separate juvenile court during such period or the Chief Justice of the Supreme Court may designate and appoint a judge of the district court, a judge of another separate juvenile court, or a judge of the county court to serve as judge of the separate juvenile court during such period. The Chief Justice may also appoint a judge of a separate juvenile court to hear juvenile matters in a county court.