National and Midwestern managed care companies are joining forces to serve multistate employers.

CIGNA HealthCare, a unit of CIGNA Corp., Philadelphia, and HealthPartners, Bloomington, Minn., will sell multistate employers plans that offer Minnesota employees access to the HealthPartners provider network and employees in other states access to CIGNA’s national provider network.

CIGNA and HealthPartners are aiming the plans at the 6,000 Minnesota-based employers that have employees working outside Minnesota, the companies say.

CIGNA has formed similar alliances in the past year with Tufts Health Plan, Waltham, Mass., and Health Alliance Plan, Detroit.