But I don't think the software can differentiate between the ideas of defined and undefined characters. It's all just association between words and aesthetics, right? It can't know that "Homer Simpson" is a more specific subject than "construction worker" because there's no actual conceptualization happening about what these words mean.
I can't imagine a way to make the tweak you're asking for that isn't just a database of every word or phrase that refers to a specific known individual that the users' prompts get checked against and I can't imagine that'd be worth the time it'd take to create.