Valley Medical Group. Nursing (Nurse Practitioner), Physician Assistant (PA) • 4 Providers. 179 Northampton St Ste H, Easthampton MA, 01027. Make an Appointment. (413) 529-9300. Valley Medical Group is a medical group practice located in Easthampton, MA that specializes in Nursing (Nurse Practitioner) and Physician Assistant (PA)..