Massachusetts General Laws
Chapter 231b - Contribution Among Joint Tortfeasors
Section 2 - Pro Rata Shares of Tortfeasors in Entire Liability; Determination

Section 2. In determining the pro rata shares of tortfeasors in the entire liability (a) their relative degrees of fault shall not be considered; (b) if equity requires, the collective liability of some as a group shall constitute a single share; and (c) principles of equity applicable to contribution generally shall apply.