As far as I try to understand your problem. I think your data should transform into require format then it will be possible
Please attach the twbx file with sample data set.
You may try this,
Create a calculated field like this and use it in your view
IF [Procedure Type]="A1" OR [Procedure Type]="D1" THEN "Neurology (includes A1 and D1)"
ELSEIF [Procedure Type]="B1" OR [Procedure Type]="C1" THEN "Pediatrics (B1 and C1)"
ELSE [Procedure Type]
Let us know if this help.
If you grouped it that way then A1 and D1 are in the group Neurology (which is correct). But I can't count the numbers for A1 and D1 separately, which is also what I needed.
Thanks for trying.