[iki1lu4fun]

Hi,
I've got a little problem.
Maybe it's better to start at the beginning:

I am reading the books "a song of ice and fire" in german on my Kobo Glo. When I started I noticed unneccesary and inappropiate translations and it really disturbes me. Then I found out that they did that new translation since 2010 but I can't find the old versions in EPUB. So I decided to do a little work and change the "dumb" words into the originals with Sigil. Till this point everything is ok, but I couldn't find a way to apply the changes on more than one Epub file.
There are more than 80 words in each book I want change and there are 10 books and I might freak out if I'd have to change round about 800 words. I would be so grateful if there's anyone who can help me and tell me how to edit every book simultaneously. If there isn't a way with Sigil maybe with another programm.
Well, thanks in advance!
Julian