If you are going to require or even emphasize mediation as a resolution, then you need a better mediator than the South Bay Center for Dispute Resolution. I have participated in one of their mediations and found them rather dissatisfactory. I have received anecdotal affirmations of my opinion, that their methods rarely have favorable results, nor have you assessed their efficacy. Your role s/b to make sure a problem doesn't reach that level and your employees s/b evaluated to that end.