Auto Numbering / System

Hi,

I am wondering is there a way to have an auto numbering column where the display format is dependant on the value of another column.

I have a "Type" column that is a dropdown with "Action" and "Decision" as the values. I would like the Auto number to display A-001 if this column is "Action" and D-001 if it is "Decision".

Where it gets difficult is that the number counts must count the occurrences separately. (See the attached screenshot for an example).

If there is a way of formulating this, I would be very grateful to see how it would work.

Thanks!