According to NH RSA 281-A:5, every employer who employs individuals on a full or part-time basis is required to obtain Workers' Compensation Insurance for those employees. It does not matter if the employees are related either to yourself or each other.
RSA 281-A:2 VIII states that if a corporation or limited liability company has three, or fewer, executive officers or LLC members, and does not employ any other individuals, obtaining coverage is not mandatory but may be elected pursuant to RSA 281-A:3. In the event a fourth executive officer or LLC member joins the company, Workers' Compensation Insurance must be purchased.
Once coverage is in place, everyone in the company, including all officers or LLC members, are considered employees and automatically covered. Up to three executive officers or LLC members may then elect to be excluded per RSA 281-A:18a. Every employer who is subject to the Workers' Compensation statute, RSA 281-A, or who elects to accept its provisions, must post a notice at the business that the employer is working under the provisions of this chapter.