SECTION 380:1-5-5. Joining of other parties affected by rule

  If, at any time, it appears from the papers filed or from evidence adduced that the interests of persons other than the petitioner are so affected by the requested ruling that it is improper to entertain the proceedings without hearing them, the Labor Commissioner may refuse to issue a declaratory ruling, or, in his discretion, he may require them to be made parties, and if the matter can be so handled consistently with the public interest and the efficiency of the Labor Department's procedures, then in that event, notice shall be served upon them, as in individual proceedings, and the matter will be governed thereafter by the procedure applicable to individual proceedings.