Hi Kale99,
First of all, each look up field could only be associated with one entity.
So if you mean you want to classify the records of the same entity in a look up field, you could add a custom field to store the category and then create different views by category. When you use lookup filed to find record, you could use views to filter data.
If my understanding is not correct, please kindly share more information about your requirement so that we can help you better.
Hope it helps.
Best Regards,
Leo
