Link sections of two or more resources

You should be able to add the selected text as an additional anchor to the note / highlight

If you can’t see how to do it, please post back and I’ll post some screenshots when at my computer 

Since Graham can't get you screen shots right now

Highlight the desired commentary text

Right anywhere in the highlighted section

Select Open Annotation

Add Anchor

Note that when you add the anchor, you will be given the opportunity to add a Reference (James 4:8 in the screenshot) or Selected Text

If you add it as a reference, the anchor will apply to all your versified resources. If you select the text in a specific bible, it will only apply to that bible.