Doctors at Palm Drive Medical Center in Sebastopol have become part of Prima Medical Group, a Marin County-based physicians group that is making further inroads into Sonoma County.

The five doctors who are now part of Prima Medical Group include family medicine physicians Constance Ayers, Gregory Rosa and Harry Simms. The other two are neurologist Allan Bernstein and internal medicine and pediatrics doctor Misty Zelk.

The three physicians were part of Palm Drive Medical Center, which was founded by Palm Drive Hospital in 2008 to recruit and retain doctors.

Prima will allow its member doctors to better serve their patients and help Palm Drive recruit physicians to the area, said Tom Harlan, CEO of Palm Drive Hospital.

"We are delighted to have Prima Medical Group on our campus," he said. "This is a long awaited change on the part of patients, physicians and the hospital."

Prima Medical Group, through the Prima Medical Foundation, is affiliated with Marin General, Sonoma Valley and Palm Drive hospitals.