I quote below the pertinent RSA:
91-A:2-a Communications Outside Meetings. –
I. Unless exempted from the definition of "meeting'' under RSA 91-A:2, I, public bodies shall deliberate on matters over which they have supervision, control, jurisdiction, or advisory power only in meetings held pursuant to and in compliance with the provisions of RSA 91-A:2, II or III.
II. Communications outside a meeting, including, but not limited to, sequential communications among members of a public body, shall not be used to circumvent the spirit and purpose of this chapter as expressed in RSA 91-A:1