ANNUAL SICK
A B C D E F G M
N O
Row 8 A, S A A S A S A
Row 9 1.0, 7.0 8.00 8.00 8.00 8.00 8.00 8.00 33.0
0.0 23.0

As you can see, Cell A9 has two leave "hours"; one for A (1.0) and one for S
(7.0).

I would like:

Colmn M, row 9 to show 33.0 (all of the "hours" related to A from row 8); and
Column O, row 9 to show 23.0 (all of the "hours" related to S from row 8)