N.H. Rev. Stat. Ann. § 31:9-a

A town may at any legal meeting vote to sponsor a group life, accident, medical, surgical and hospitalization insurance benefit or any combination of such benefits for regular employees of the town and their dependents under which plan said employees agree to pay the premiums. In such case the town treasurer is authorized to withhold from the compensation of such employees who agree to such plan the amount of the premiums and pay over the same to the company furnishing such benefits.