The Labor Department released a final rule to narrow the situations in which multiple businesses share liability for paying workers their wages, a key element of the Trump White House’s effort to roll back the Obama administration’s more expansive definition of “joint employment.” The new rule, which takes effect March 16, satisfies one of the business lobby’s top priorities. It limits the circumstances under which employers, such as a franchiser and its franchisees, can be considered to jointly employ a group of workers under federal wage-and-hour law, thereby making them responsible for paying minimum wages and overtime.