The Labor Department released a final rule to make it easier for small businesses to band together to create joint 401(k) retirement plans for workers, the Wall Street Journal reported. The rule, which takes effect Sept. 30, broadens the ways companies could join together to offer retirement accounts. Under the rule released yesterday, companies in different industries — for example, landscaping companies and real-estate firms — could create a joint plan as long as they are located in the same state or metropolitan area. The rule also would clarify that similar companies — for example two landscaping companies — located in different regions of the country could join together. Such arrangements, often called multiple-employer plans, are currently limited to employers with an affiliation or connection, such as a common owner or being members of an industry trade group. The rule means local chambers of commerce are more likely to sponsor retirement plans for companies affiliated with them.