@lyn2012, @dordale:
You can let calibre manage collections on your Kindle, if you jailbreak it. Amazon removed the ability post-K3 (I think because someone managed to FUBAR their book index, so they couldn't find their books, by messing with it) but all that means is the controlling files were moved off the USB drive section. Use the Kindle Collections plugin, the modified version found here:
https://www.mobileread.com/forums/sho...18#post2263518.
You may also want the K5 collections hack - I haven't used either, but I think the plugin
may depend on communicating with the hack -- here:
https://www.mobileread.com/forums/sho...d.php?t=186305. It's not compatible with firmware v5.4.2, but you can downgrade if needed.