add the discipline where? The only place where disciplines are listed is in the csl styles and those are very general - so nuclear engineering would be too specific. Otherwise, you need to be more specific about what you need.

You could create the group yourself.

Well, those disciplines are necessarily limited in number. Every group is a bad fit for its disciplines-- since people are more likely to find your group via search than by browsing, just make sure that it has an informative name and description. The nominal discipline is never going to work well.