A rift between plaintiffs firms in New Jersey and New York is threatening to disturb a proposed $350 million class action settlement between the American Medical Association and the United Healthcare Group and is affecting the pursuit of actions against three other insurers.

For nine years, attorneys now at Wilentz, Goldman & Spitzer in Woodbridge, N.J., and at Pomerantz Haudek Block Grossman & Gross in New York have been co-counsel for the AMA, doctors and insureds in the suit against UHG in federal court in Manhattan.