Finding "subtext" within a cell for Pivot table

I am creating a spreadsheet for a book fair. Each record contains the title of the book, author, ISBN… , book categories, specific interests, relevant school subjects and so on. I used dropdown menus for several fields, like book categories and specific interests. Using VBA code, I allow the user to make multiple selections from many of the dropdowns. The selections are stored as one string.

Here’s the problem:

I want to include a pivot table so that the user can find specific books based on search criteria. So, if the user wants to find all Science books that are offered, she can go to the pivot table builder, choose School Subject as a filter and click Science. Unfortunately, the pivot table has Science in many combinations. So the user has to check Science, Science and Social Studies, Science and Life Skills, ….

I’d like to be able to just click Science. Then any book that has Science, with or without other subjects, will show up. Will this require more code? I guess another way to say this is that I want the pivot table to separate the text within each field and return the books’ titles if they contain the “substring” Science.

Is this doable?