Hadn't tried this in awhile but after seeing "The IVP Bible Background Commentary: New Testament" pop up as my top-ranked Passage guide commentary option, I figured something had to be done.
I don't know when this came about, so it could be old news to some, but prioritizing collections seems functional.
There are existing collections for commentary sets. I found this out in Beta 4, I think, when revisiting collections I'd made to cover commentary sets and found them to be inexplicably duplicated. I removed the collections I'd made by rules/filtering but hadn't thought to try prioritization then.
Tried it tonight, and it worked just like I thought it should. I opened the Library, typed in "NIGTC", grabbed a vol and shoved it into the prioritization list. The collection name showed, not the individual volume. Cool. So I quick added some other series to the list. Now my Passage Guide is as it should be.
