'Series' grouping within iBooks - How do you create them? (Pic included)

[HelixOmnimedia]

I've noticed since Harry Potter enhanced edition making the news that these Samples/books are grouped together in 'Series' - I downloaded samples of Twilight to see if it was just the enhanced, its not.

I have about nine series of books that I read and would love to group them like this instead of creating 'collections'

Any idea how these 'series' group are created?

 

[HelixOmnimedia]

I've noticed since Harry Potter enhanced edition making the news that these Samples/books are grouped together in 'Series' - I downloaded samples of Twilight to see if it was just the enhanced, its not.

I have about nine series of books that I read and would love to group them like this instead of creating 'collections'

Any idea how these 'series' group are created?

Played around with this all day with no joy.

Followed the Apple 'support article' on metadata but it won't allow you to edit the "Series Name" field.

Even tried Calibre but still no joy with making the metadata stick.

I guess to have your books grouped together as a series you need to buy them directly from iBooks.