I have a real challenge. I am trying to summarize a large data set.
I need to determine the number of different employees involved in delivering
service per specific reservation, if the service type and product match
criteria.

Sample data:
type product res_num emp_num
A IA 3 50
B IA 2 60
B R5 1 60
B R5 1 60
B R5 2 60
B R5 2 80
B R5 2 80
C IA 3 40

If type = B or C
And if product = R5

Calculate number of different emp_num utilized per res_num

Sample result:
Res_num Different emp_num
1 1
2 2

Is there a formula(s) that will do this?

Thanks