Section 20(1) in Industrial Disputes (Punjab) Rules, 1958
(1)Where there are numerous persons as parties to any proceeding before a Board, Court, Labour Court or Tribunal or an Arbitrator and such persons are members of any trade union or association, the service of notice on the Secretary, or where there is no Secretary, on the principal officer of the trade union or association shall be deemed to be service on such persons :Provided that where personal service on the Secretary or the Principal Officer is not practicable, the service of the notice may be effected by affixing a copy of the notice on the outer door or any other conspicuous part of the office of the trade union or the association.
