Update: I was able to create a work-around. I covered the pie charts with a floating blank portlet. Unfortunately, this disables the ability to use an action filter, but I removed those and added a button off to the side. It works. If anyone has a better idea, then feel free to share!
If you want to take it a step further, you can lay several smaller text boxes only covering up the exact area that the outer layer encompasses (leaving the inner white circle uncovered). Depending on how precise you want to get, you could make them as small as one pixel so that you can go around the curves of the donut, but let's be honest - you've already solved your own question!
I can post a copy of one if you would like.