91. The Units, whether Provinces or Federated States, shall have no power to enter into separate alliances and treaties of political character amongst themselves, provided that with the consent of the Federal Legislature
(a) a number of Federated States may combine together to form a Sub-Federation in accordance with the provisions of this Constitution;
(b) a Federated State may attach itself with a Province for certain specified purposes in accordance with the provisions of this Constitution.
(c) a Federated State may hand over to the jurisdiction of Federal or provincial authorities functions vested in the State.