Is it possible to create "folders" in calibre?
Some books I have are divided in various PDF's and I don't want to merge them, then I was thinking if it's possible to create folders in Calibre. For example:
+ Splitted book
And then when I click the +, It's gonna show:
- Splitted book
|---Part 1.
|---Part 2.
|---Part 3.
|---Part 4.
|