Counting Patients one time

I have a data set that has patients who have their main Doctor. We are doing a count per Doctor ( of patients); but also we include their classification;

if they are considered sick or regular.

Within sick we have 3 types. Let's just call it A, B, or C.

The thing is, some patients have diagnosis for all 3 as well as regular; many have 2 + regular, and 1 + regular.

So we don't want to count the patient 4 times but only once. We would want for example, if they have A as well as others, the patient would be Diag/ A

if B, B etc. and then only show them one time with the 'A' or 'B' etc.

How do I make such a formula to decide how to show only one row?