Excluding features from section view

Hi,

Is it possible to exclude certain features that have been united with the rest of the solid body from a section view?

I've got 2 rings revolved. In between the rings I've created a surface for impeller vanes. The vanes have been united with the 2 revolved rings making the whole part 1 solid body.

How do I exclude the surfaces and everything from a section view so that I only section the 2 revolves?

Is it possible or should I just find an easy way to work around this by inserting a "copy" part into the drawing of the 2 revolves and then section that?

Thank you.