Notwithstanding anything contained in section 3, all suits, cases and other legal proceedings between parties all of whom belong to the Scheduled Tribes specified in item 2 of Part I—Assam, of the Schedule annexed to the Constitution (Scheduled Tribes) Order, 1950 or such other tribe or tribes, as may be specified in this behalf, shall be tried and continue to be tried under the Rules for the Administration of Justice and Police in the Sibsagar and Nowgong Mikir Hills Tracts as if this Act has not been passed.