It would be a little tricky but it can be done.
Basically you need to modify the SPOSTARBUST_query_related_posts function so that accept some additional optional params for this catagory. Then add the params to the $tags_query array (if passed).
Then just test for that category in the SPOSTARBUST_related_links_on_posts or the widget function and pass the extra param if it was in that category.
Hope that helps. Let me know.
I'm not in a position to donate any of my time to code changes for this free plugin right now. I've put in a lot of work already and only gotten a couple small donations over the last year. got to work on stuff that pays my bills right now.