Mass. Gen. Laws ch. 212 § 20A
The superior court may in counties where more than one session is held simultaneously for civil or criminal business or for civil and criminal business require that jurors be held in a central pool and assigned to the several sessions in such manner as the court shall order. It may in its discretion order that writs of venire facias for jurors issue for the total number of jurors required for all sessions at any sitting without specifying therein that they are required for civil or criminal business. Jurors so drawn shall be subject to be used interchangeably for civil or criminal business.
The chief justice of the superior court department, in consultation with the court administrator, may designate not more than three officers appointed under section seventy of chapter two hundred and twenty-one to attend the central pool of jurors in the county for which they are appointed. The officers so designated shall perform their duties under the direction of the court, and receive such compensation as the court administrator shall establish, except that in Middlesex county the juror pool officers shall receive a salary of not less than twenty-eight thousand one hundred and seventy dollars per annum.
Mass. Gen. Laws ch. 212, § 20A