I use a custom column for that. It's called '#link' and is a tag-like text column shown in book details. There, I add the same tag for books to be linked with each other (and those books only). In this case I would probably use something like 'Father Brown' as the tag. When you click on the tag, you get the search for all books with this tag.
It's not perfect (you won't go directly to the omnibus) but it is pretty usable. (And it's kinda like the solution suggested by @BetterRed
, although I don't use Quickview for that.)
My Calibre dream would be, though, to be able to provide direct links to the books, accessible from the inside and the outside of Calibre.