(a) A lawyer who is admitted only in a non-United States jurisdiction shall not, except as authorized by this Rule or other law, establish an office or other systematic and continuous presence in this jurisdiction for the practice of law, or hold out to the public or otherwise represent that the lawyer is admitted to practice law in this jurisdiction. Such a lawyer does not engage in the unauthorized practice of law in this jurisdiction when on a temporary basis the lawyer performs services in this jurisdiction that:
(1) are undertaken in association with a lawyer who is admitted to practice in this jurisdiction and who actively participates in the matter;
(2) are in or reasonably related to a pending or potential proceeding before a tribunal held or to be