Marx Barnes commented in the L4 forum that the collections syntax was limited to 200 characters
http://community.logos.com/forums/t/6819.aspx
He was trying to limit a collection to just the Gospel of John and exclude the epistles and Revelation. It got me thinking, how about a syntax that lets us limit books that have a specific active index (is this the right term?) range in a book. So, if a commentary is tagged with the versification of the Gospel of John it could be put into the collection.
So this syntax could look something like Bibref:john (this would then grab any commentary that deals with the Gospel of John.)