[weberr]

I unfortunately have a humongus epub -- "The Complete Works of ..." -- consists of 12 books each with as much as 20 chapters with every chapter a separate html file. I would like to create a number of those books into individual stand-alone epubs. Does either Sigil or Calibre Epub editor have some way to select a set of html files and create an epub using those selected files? Only way I have found that works is so tedious:
1. Use calibre to create an empty epub and open it in 7-Zip.
2. Open the master epub in 7-Zip and copy the selected html files into a folder.
3. Use the Sigil file import function to import the set of html files into the empty epub.
4. Copy the style sheets from the master epub into the new epub.
5. Copy the appropriate image files from the master into the new epub.

Wish I could simply select the html files and right-click them into an epub.

Anybody got a more efficient process?