There is a HIPAA/ERISA exemption for on-site medical clinics, but I can't find a definition of what an "on-site medical clinic" is.

The clinic I'm analyzing is physically located away from the employer's offices, but nurse clinicians perform MOST of the services on the employers premises. Some services are performed at the clinic. (e.g., if an employee misses his on-site flu shot or annual physical, then he can go to the nurse's clinic off-site and get the shot/physical, etc.)