Exactly, how did you do that? What I actually did to get it done was to create a sketch of the profile I wanted, then revolved it to get everything except the two holes. Next step is to just add the two 4" holes. Although this method isn't as intuitive to me, it worked really well. But I would still like to know how to use the groove tool a whole lot better. Most of the tutorial are grooving the sides of a cylinder, I tried to do the same thing with the face of this cylinder, but could not get it to do what I wanted. I have attached the new drawing.
First, I turned the inner circle of the first sketch to construction geometry: