B-1, r. 3.1 - Code of Professional Conduct of Lawyers
79. A lawyer must not engage in his professional activities with respect to a matter in which:
(1) he or another person within the same firm or who has an interest therein is carrying out or has carried out functions as a judge or member of a tribunal; or
(2) he has been engaged as a member or representative of a public organization, such as a government, a municipality or a school board, unless he represents such organization.