WASHINGTON (Reuters) – Credit Suisse Group AG entities, among six defendants in a lawsuit originally filed by Iowa Public Employees Retirement System and other retirement associations, has agreed to pay $81 million, the first to agree to settle, the law firm Cohen Milstein Sellers & Toll PLLC said in a release. “This first settlement agreement includes both an $81 million cash payment and an obligation on the part of Credit Suisse to provide cooperation to plaintiffs in litigating and ultimately trying their case against the remaining defendants,” lawyers for the plaintiffs said in a court fil…