You will need to look for a tempering valve at a plumbing supply house. The one thing you have to make sure to check is the lowest output temperature because most of these are designed to temper HOT DOWN, not COLD UP. The valve is easy to connect to your hot and cold water faucets with hoses, but you have to put a backflow preventer or one way flow valve on each side to prevent the hot and cold water from mixing and leaving you with a water heater full of warm water. Depending on how many washers you are feeding with the tempered cold water, you can use one of those three or four valve manifolds that are sold in the garden centers of HD or Lowes.
I know that you will like your tempering valve and wish you success in getting it set up. I really like mine and do believe that the tempered cold water rinses better than stone cold water.