Upon application by two or more attorneys for the Commonwealth, the Chief Justice of the Supreme Court, or any justice designated by the Chief Justice, may within twenty days thereafter order the impaneling of a multi-jurisdiction grand jury for a term of twelve months. The term of such a grand jury may be extended for successive periods of not more than six months by the Chief Justice, or by any justice designated by the Chief Justice, upon the petition of a majority of the members of the grand jury. The impaneling order shall designate the jurisdiction requested on the application as the jurisdiction where the multi-jurisdiction grand jury shall be convened and shall, unless all judges of that circuit have recused themselves, appoint a judge of the circuit court of that jurisdiction as the presiding judge. The impaneling order shall also designate special counsel and each special counsel who will assist the multi-jurisdiction grand jury as listed in the application. The presiding judge shall substitute or appoint additional special counsel upon motion of special counsel.