The U.S. Supreme Court…agreed to decide whether Wal-Mart Stores Inc. must face a gender-bias suit on behalf of potentially 1 million of its workers. The justices today said they will review a federal appeals court decision that approved a single suit to cover the claims of women who worked at the retailer’s 4,400 Wal-Mart and Sam’s Club stores since 2001…Wal-Mart says that any problems were isolated ones and that the claims of women around the country would be too varied to proceed fairly as part of a single case…Wal-Mart says the case would be so unwieldy it would violate the procedural rules that govern civil cases in federal court and the Constitution. [also refers to Costco, Altria Group]