In issuing the notice of hearing, the commissioner will designate as parties any persons known to the commissioner whose legal rights, duties or privileges are being determined in the contested case and any person whose participation as a party is then deemed by the commissioner to be necessary to the proper disposition of such proceeding. Subsequest to the issuance of such notice no other person shall have standing as a party except upon the express order of the presiding officer.
Conn. Agencies Regs. § 17-210a-18