In Huber v. Taylor, (U.S. Ct. App., 3rd Cir., Oct. 31, 2006), read opinion here, the U.S. Court of Appeals for the Third Circuit defines the duty of loyalty that all lawyers, even co-counsel (and local counsel)  from different firms, owe to clients. In startling brusque language, the court describes the burdens of that elevated standard of conduct as the cost of doing business for a lawyer. This is a small sample quote:

 "We are embarrassed to have to explain a matter so elementary to the legal profession that it speaks for itself: All attorneys in a co-counsel relationship individually owe each and every client the duty of loyalty. For it to be otherwise is inconceivable."

The blog called Point of Law has more commentary on the case. Here is the link: | PointOfLaw Forum: "3rd Circuit Revives Case Against Asbestos Class Action Lawyers"