12 C.F.R. § 269a.2
The term party in interest means any person, employee, group of employees, labor organization, or bank that will be or is directly affected by the resolution of any charge, complaint, petition, application, or request presented to or being considered by the panel or its designated officers. Any (a) labor organization (not a charging party nor a charged party) attempting to organize the employees of a bank or that is or was recently a party to a collective bargaining agreement with a bank named as a party in a charge, complaint, petition, application, or a request, or (b) bank (not a charging party nor a charged party) that acts as the employer of any person named in a charge, complaint, petition, or request shall be deemed to be also a party in interest and shall be entitled to notification and service of all relevant procedures and documents.
12 C.F.R. § 269a.2