A new final rule from the Labor Department makes it easier for small businesses to join together to offer their workers 401(k) plans.

The rule goes into effect on Sept. 30.

As a result of the new rule, smaller companies can now leverage the bigger scale of a combined group of businesses to negotiate lower fees on their 401(k) plans.

Under the rule, companies in different industries, for example marketing firms and landscaping companies, can create a joint retirement plan as long as they are based in the same state or metropolitan area. Similar companies, such as two real estate firms, located in different areas of the country can also band together and create a plan.

However, companies in two different industries that are located in two different regions may not form a plan together under the rule.

Currently, multi-employer plans such as these can be created only when employers have a common owner or are both members of the same industry group.

The new rule opens the door for local entities, such as chambers of commerce, to sponsor retirement plans for companies in their networks.

The Trump administration supports the rule as a way to make it possible for more employees of small businesses to obtain retirement benefits.