So you have your tracks ordered properly right?
You might think so, but this one tiny hack/trick is awe inspiringly good and incredibly simple.
Create an empty silent track, use audicity or the like to do this.
Drop this empty track into a playlist and separate the tracks that work really well together with this empty track.
It'll look something like this.
I know right, it's epic, it's simple, and visually it immediately creates groups.