Why can't you select whole Collections of books in iTunes to synch to your iPad?

Wondering why iTunes won't allow you to select Collections from the iBooks app to synch to your devices. Much like iTunes handles music and playlists, it would make sense, if you had created a collection called "Summer Reading List" or even "Odd Thomas Series" that you would then only have to select the name of the Collection in iTunes to load all (or all checked) books from that collection to your device.