What is the dressing recipe for Costco's greek pasta salad?

i would love to make this pasta salad at home and i cannot get the dressing to taste right. does anybody know how to make the dressing that goes on this?What is the dressing recipe for Costco's greek pasta salad?
The ingredients in most greek salad dressings are:

Olive oil

Vinegar and/or Lemon Juice

Dried Oregano, preferable greek

Salt %26amp; Pepper to taste



My only other suggestion would be to check out the ingredients on Costco's Greek Salad, eliminate the actual salad and preservative ingredients and you should wind up with the salad ingredients.