Medical Referral Tracker please!

Hi! I work in a clinic and we are trying to update our referral tracker. Each patient on the tracker has a diagnosis category (4 broad diagnosis) that 99% of our patients fall under. And then in those categories there is smaller subcategories. This is a cardio-genetics clinic. So we have a broad category of Connective tissue disorders and the smaller categories would be syndromes such as EDS and Marfan. We want to be able to filter and sort the sheet by diagnosis. The genetic doctor presents his numbers and wants to be able to filter and show how many Marfan patients we have on the tracker and then filter again for how many patients have cardiomyopathy. Is there a way to set up these columns like that so we can filter them over and over by the results? I’d love if I could get some help on how to make it useful for the team.