Mass. Gen. Laws ch. 53 § 121
A town in which official ballots are used, may at any annual meeting vote to hold a town caucus for the nomination of candidates for town officers required to be voted for by official ballot at its annual meeting and after such vote has been in effect therein for a period of not less than three years may, by a vote at a meeting held at least sixty days before an annual town meeting, rescind such action. Such caucus shall be called by the selectmen in the same manner as provided in section one hundred and eighteen for the calling of other caucuses and shall be called to order by the town clerk who shall preside until the election of a chairman. Except as aforesaid, the town clerk shall not act or serve as a caucus officer. The town in town meeting may determine whether nominations shall be made separately or partly or wholly on one ballot, and may within the limits defined by law, prescribe the day and hour when such caucus shall be held and how long the polls shall be kept open, and make provision for the preparation and use of ballots. Such action may be altered, amended or rescinded at any future town meeting but shall continue in effect until so altered, amended or rescinded.
At a town caucus held under the provisions of this section the two persons receiving the highest number of votes cast for the nomination of candidates for an office shall be declared nominated for such office; but, if two or more persons are to be elected to the same office at such election, the several persons, to a number equal to twice the number so to be elected to such office, receiving at such caucus the highest number of votes, the second highest number of votes, and so on to the number to be nominated shall be the candidates whose names shall be printed on the official ballots to be used at such election. If the caucus results in a tie vote among candidates for nomination receiving the smallest number of votes, which, but for the tie vote, would entitle a person receiving such number to have his name printed upon the official ballot for the election, all candidates participating in such tie vote shall have their names printed upon the official ballots, although there be printed upon them the names of candidates to a number exceeding twice the number to be elected.
If a person receives less than eight per cent of the votes of those voting for candidates for such office, he shall not be declared nominated therefor, although thereby the number of names to be printed upon the official ballots will be less than twice the number to be elected.
During such time as town caucuses are held under this section in any town, no political or municipal party caucus shall be held therein for the nomination of candidates for town office. The provisions of sections one hundred and seventeen to one hundred and twenty, inclusive, so far as applicable, shall apply to caucuses held under this section.
Mass. Gen. Laws ch. 53, § 121