From the lack of responses I assume that either I wasn't clear enough with what I was asking, or maybe it's not possible.
But just in case someone else might have this type of question in the future, I'd like to explain what I ended up doing:
Since all I really wanted was to have the book's title in the jacket, but to also add the series information in the file name, I ended up cleaning my book title and removing the series name and index, and instead, I edited the save to disk template so when I save to my backup folder, the file name does include the series name and index, in my desired format:
Code:
{series} {series_index:0>2s|#| - }{title} - {authors}
I followed the instructions here:
https://manual.calibre-ebook.com/template_lang.html