Can a former court commissioner be disqualified from handling a matter which he had previously heard as a judge?

In Higdon, while the former court commissioner was personally disqualified from handling a matter which he had previously heard as a judge, the remainder of the firm could avoid disqualification so long as it was proven that he had been and would continue to be screened from any participation in the case. We recognized there that existing California law resulted from very different circumstances concerning practicing attorneys changing employment and " 'California precedent has not rushed to accept the concept of disqualifying the attorney but not the firm, nor has it enthusiastically embarked upon erecting Chinese walls.' " (Higdon v. Superior Court, supra, 227 Cal.App.3d 1667, 1679, 278 Cal.Rptr. 588, quoting Klein v. Superior Court (1988) 198 Cal.App.3d 894, 912, 244 Cal.Rptr. 226.)