Short answer is no - you can’t restrict a fine-tuned model to answer based on only some of the fine-tuning.
Longer answer: you might not want to anyway. Let’s imagine your content is something dynamic, like a bunch of user profiles from a social network. If you managed to fine-tune it to consistently answer questions about “Cody” based on his profile, you’re going to get out-of-date answers. So now you’re not just trying to limit your scope based on “who’s profile” but over timestamps/history points as well.
I’d encourage you to keep your thinking framed to “what can I pass in the prompt”. That way you’re not trying to fine-tune your model to “know” you’re data - you’re trying to fine-tune your model to get really good at completing prompts that contain fragments of your kind of data.
That’s more do-able and more re-usable extensible.