It was disconcerting every time I went to the Contacts app. My instinct was to look for "doctor," and I had to pause and think of what the first initial of the doctor's last name was. Then it hit me: Make their last name start with "Dr."
This is what I see under the D's in my contacts list now:
The idea is marvelously simple:
If your contacts list is alphabetized by last name, add "Dr" before the doctor's last name.
If your contacts list is alphabetized by first name, add "Dr" before the doctor's first name.
This will group all of the doctors in your contacts together. And now you (and anyone else you trust with your phone) can easily find the contact info for your doctors!