Physicians Plus is suing UW-Madison?s doctor group, saying the doctors? threat to stop treating the insurance company?s patients is illegal. Physicians Plus, owned by Meriter Health Services, says the doctor group, UW Medical Foundation, demanded fees that are too high. After Physicians Plus refused to pay the fees, it says the doctor group threatened to stop serving most of the insurance company?s patients starting in 2013. The doctor group says it?s still negotiating.