Bring large pot of salted water to boil over high heat. Add oil, then the macaroni. Bring to a boil and cook until the macaroni is just tender (5-7 min). Drain well. Return to pot.
In small saucepan, melt butter. Stir into macaroni.
Take about 1/4 c. of each of the cheeses and set aside. Add the remaining cheeses, one at a time, to macaroni.
In a small bowl, beat eggs and add to milk, then add to macaroni. Season with salt and pepper.
Pour macaroni into a deep greased casserole dish. Sprinkle remaining cheeses on top. Bake at 350 degrees for 35-40 min. until bubbling around the edges.