I find a great way to section-off different parts of a list (that you want to keep on one level for some reason) is to use the horizontal line available in the Powerpack add-on.
You add a bullet with three dashes and it renders as a horizontal line across the width of your list. It’s not quite the same as white space but for me serves a similar visual purpose.
Obviously you need to use the Powerpack add-on (see: Powerpack 3) which you may not wish to use but it is full of useful features.
What you type
How it looks
It would be great for people who don’t use Powerpack if this was a standard feature.