The following answer is the reverse of what you've asked for but it might be of use to help clean up your library. The directions are to manage tags in your library - correcting multiple "sci-fi" situations.
Open the Tag Browser (luggage tag icon at lower right of Calibre screen).
Alter Tag Browser (above currently running Calibre version #, bottom left).
Manage authors, tags, etc.
Manage Tags
The Category Editor (Tags) window will open.
Now you've got a list of every tag that is currently in your database. You can edit any or all of them as you see fit. To do so you need to highlight a tag in the first column, press the "blue i" button to edit the selected tag. Change the term to whatever you prefer and press enter. Calibre will change the various book records and return control back to you when completed. You can merge tags by giving them the same exact term. Rinse and repeat as needed.
If your library includes metadata downloads it is possible you are going to encounter lots of alternate spellings or phrasing of the same tag/term. I would suggest looking through every tag in your library. Although this might entail a lot of work, it will certainly clean up your library and increase responsiveness (less cpu cycles to process the decreased data load).
You might want to consider how you're going to deal with naming conventions and complex tags before you start this project. For instance a tag like "Fiction - General (Fantasy)". I opted with "Fiction", "General", "Fantasy". Naming affects Searches; for instance do you search for "Dwarf" or "Dwarves" (note the spelling change will cause different search results). I opted to use terms based on plural word forms - so my library has "Dwarves" even if there is only one dwarf in the entire story. Maybe you would rather have both singular and plural. Dates and numbers will also be an issue.
After you've got the tag situation resolved, you should be able to do some tag related searches and add the name of the Sony collection(s) to the appropriate books. Thereafter things should be in sync.
I'm sure that there are other ways to do this - and I'm just as sure that someone else will chime in.
