Section 20(1) in Industrial Disputes (Central) Rules, 1957
(1)Where there are numerous persons as parties to any proceedings 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.
