(a) With respect to any determination under this part concerning the status of a person as an employer under the Railroad Retirement Act and the Railroad Unemployment Insurance Act, that person shall be a party to such determination and may submit written briefs or argument, as well as any documentary evidence pertinent to the matter at issue, to the decision maker to be considered in the rendition of a determination. The employees of such person may submit written briefs or argument with respect to such determination, but shall not be parties thereto.

(b) With respect to any determination under this part concerning the status of an individual or group of individuals as an employee or employees of an employer covered by the Railroad Retirement Act and the Railroad Unemployment Insurance Act, the employer alleged to be the employer of the individual or group of individuals and the individual or group of individuals shall each be considered a party to such determination and may submit written briefs or argument, and documentary evidence pertinent to the matter at issue, to the decision maker to be considered in the rendition of a determination.