The Office of Personnel Management shall prescribe regulations under which an employee participating in a leave bank program under this subchapter may, subject to such terms or conditions as the Office may establish, also make or receive donations of leave under subchapter III.

Notwithstanding any provision of section 6337 or 6371, if an employee uses leave transferred to such employee under subchapter III and leave made available to such employee under this subchapter in connection with the same medical emergency, the maximum number of days of annual leave and sick leave, respectively, which may accrue to such employee in connection with such medical emergency shall be the same as if all of that leave had been made available to such employee under this subchapter.