I'm attempting to gather data for Excel, but would like to place values in groups. I'm not really Excel oriented, and wanted to know if anyone could guide me in the right direction. What I want is data to be placed into groups, where you click on a value and a drop down menu opens. I understand the data validation, but I want to continually add to the data, which is confusing.

For example:

Let's say I want to look at Eastern Conference win rates in relation to given spreads. I would want to click on let's say -4, -300. Instead of my table looking like this

-4
-150
-200
-250
-300

I would want to click on the -4, have the values drop down, but then add to the list, i.e. W, L, P. Again, much like a folder when one is attempting to locate a file on the computer. Obviously I'm giving a weak example, but if anyone could help, I would appreciate it.