(1) Where there are numerous persons as parties to any proceeding before a Board, Court, Labour Court, Tribunal or National 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.
(2) Where there are numerous persons as parties to any proceeding before a Board, Court, Labour Court, Tribunal or National Tribunal or an arbitrator and such persons are not members of any trade union or association, the Board, Court, Labour Court, Tribunal, National Tribunal or Arbitrator, as the case may be, shall, where personal service is not practicable, cause the service of any notice to be made by affixing the same at or near the main entrance of the establishment concerned.
(3) A notice served in the manner specified in sub-rule (2) shall also be considered as sufficient in the case of such workmen as cannot be ascertained and found.
