duplicates of parts of a line in list

[hh]

Do you mean char 7 to 8?
And list 2 is not the result of this counting for list 1? Should be

08:00_d3_180_Monica_pink_1
10:45_d2_90_Mary_orange_6
10:00_d2_90_Mary_orange_6
10:15_d2_90_Mary_orange_6
10:30_d2_90_Mary_orange_6
10:00_d2_90_Mary_orange_6
10:00_d2_90_Mary_orange_6
12:30_d5_45_Mary_blue_3
12:45_d5_45_Mary_blue_3
12:60_d5_45_Mary_blue_3

If I got this right then try this:

function myCounter myList
 repeat for each line l in myList
   if l is empty then next repeat
   add 1 to f[char 1 to 2 of l &comma& char 7 to 8 of l]
 end repeat
 repeat for each line l in myList
   if l is empty then next repeat
   put cr & l & "_" & f[char 1 to 2 of l &comma& char 7 to 8 of l] after s
 end repeat
 delete char 1 of s -- is return
 return s
end myCounter