The administrative judge may direct that any case or class of cases pending in the court be heard by the commissioner in the manner provided for hearing of cases by law and may direct that detention hearings, informal hearings, and hearings upon any proceedings under the juvenile code and chapters 210, 452, 454, and 455, RSMo, shall be heard in the first instance by the commissioner. The administrative judge may direct such assignments on a case-by-case basis or by general order directing the appropriate designated employee of the court to assign matters to the commissioner for hearing in accordance with a general plan established by the administrative judge or by any other appropriate method determined by the administrative judge that tends to facilitate the operation of the court.