[Needlehawk]

I've been using Calibre to manage my library, and for the most part it's a godsend. However, I'm having some trouble managing series. I've got a number of "omnibus" epubs that are multiple books in a series. However, I haven't found any way to designate a single epub as (for example) number 1 through 3 in a series.

Even worse, I have at least one omnibus that contains the books from multiple series. It looks like I could put the second series in a user created column, but that still doesn't leave me a way to give it multiple index numbers of either series.

Are there any plug-ins that give this functionality, or are there upgrades planned to handle omnibus ebooks?