How to Open Correct Volume of Commentary Without the Passage Guide

I can think of two things you can do.

First use the custom short title that you can give to a book in Library view. You would give custom short title to five of the seven volumes and a second title to the other two (or however you want to arrange those numbers. Five is the most the Command Box will show). When you type one of the two short titles in the command box it should locate the correct volumes and you cans elect the one you know is right.

Second, you can make use of custom Passage Guides and a collection.

Create a Collection with just the commentary/commentaries you want to search. Create a custom Passage Guide with only one item in it: the Commentaries section. Specify the collection you just made. Name the Passage Guide.

When you right click on a passage and choose the 'Selection' tab on the right pane, your custom Passage Guide will come up on the left. Click on it and while it needs a moment to search it will come up with a link to the commentary you want.