We're having 10 for Easter dinner and my in-laws don't like rare or even med-rare beef (I know, I know). Other of our guests like it a nice pink or even a bit rare. I'm serving a beef tenderloin with a mustard crust and not sure how to get enough for 5 that is med-well and for 5 that is med-rare. Two different like-size pieces cooked for different times? Any hints?