What is the test for joint and several liability for fines in a personal injury case?

Moreover, the restitution fine "must be in accord with each defendant's individual culpability," and we held in People v. Kunitz (2004) 122 Cal.App.4th 652, 656 that a trial court order for joint and several liability for fines was unauthorized. Whereas direct victim restitution is akin to a civil judgment and may be joint and several, the restitution fine is punishment and must relate to the defendant's individual culpability. (Ibid.) The statutes for imposing fines do not authorize a fine against more than one individual. (Id. at p. 657.)