The Podiatry Practice Act shall not be construed to include (1) licensed physicians and surgeons or licensed osteopathic physicians, (2) physicians and surgeons who serve in the armed forces of the United States or the United States Public Health Service or who are employed by the United States Department of Veterans Affairs or other federal agencies, if their practice is limited to that service or employment, (3) students who have not graduated from a school of podiatry and are enrolled in an approved and accredited school of podiatry when the services performed are a part of the course of study and are under the direct supervision of a licensed podiatrist, or (4) graduates of a school of podiatry currently enrolled in a postgraduate residency program approved by the Council on Podiatric Medical Education of the American Podiatric Medical Association.