I have a listing that looks like this:

AAA 1
AAA 2
AAA 3
BB 1
BB 2
BB 3
BB 4
C 1
DD 1
DD 2
Etc.....

I want another list to link to this but only pick up the unique text entries
excluding the numbers, so the result should be:
AAA
BB
C
DD
Etc.....

If there have to be spaces in this second list then so be it, but I would
love to find a solution.