Mass. Gen. Laws ch. 183B, § 11

If all of the documents constituting the project instrument are recorded, time-shares shall not be created in any unit in a project unless expressly permitted by the project instrument. No amendment to a project instrument which is recorded shall permit the creation of time-shares unless the owners of at least eighty per cent of the units, or any larger vote required by the project instrument or by law, consent to such amendment.