You could full text search for each tag individually, then select all the books that are highlighted and add the tag. Doing that 25 times isn't that much of a hassle if you only have to do it once.
If you need to do it every single time you add a book you could find a plugin that could speed up the process— I described one possible workflow in your other thread:
https://www.mobileread.com/forums/sh...96&postcount=5