UI Nested Vertical Layout Groups

I'm trying to nest vertical layout groups as shown in the image below. I want both the internal groups and the external group to expand based on their content. To do this, I'm using a "Content Size Fitter" on each group. This approach works perfectly for the internal nested groups, but not for the external group. Instead, the external group expands, but only slightly, resulting in the internal groups overlapping when their content grows. Is there another way to approach this that I'm missing?

Thanks in advance for your help.

NOTE: Running Unity 5.3., for PC standalone build.