Sum unique values in Pivot Table without Data Model

I have a spreadsheet that tracks the surgical cases our practice sees. In this spreadsheet, each case is its own row. Column A is the date. Column B is the primary doctor assigned to the case. Column C lists which doctors are present at the practice that day (ex: "Dr.X" or ""Dr.Y" or "Dr.X/Dr.Y"). The first case of the day gets a "1" in Column D.

I am trying to use pivot tables to create a summary of some metrics for the surgeries. Part of the stats we look at are how many surgeries a doctor performed when there are two working that day vs just one.

The issue I'm running into is when I try to run statistics by the month, filtered by Column B and Column C, I cannot get an accurate count of the number of days a doctor worked that month. If I want to run stats for Dr.X on days both doctors worked, Column D only gets added if Dr.X was assigned to the first case of that day.

I know that you can add unique values by using the Data Model feature, but this isn't available on Mac. Is there any other way I can calculate this?