Sum amount based on same reference id using VBA

Hi,

If I have a excel 2003 file with a few rows/columns as follows

1234B,AB900,1
1234B,AB900,1
1244A,AB901,1
1267B,AB906,2
1279B,AB915,1
1279B,AB915,3
1279B,AB915,1
1288A,AB922,2

Is it possible to create a new line below each group of id and enter the total of column C using VBA

example:


1234B,AB900,1
1234B,AB900,1
2
1244A,AB901,1
1
1267B,AB906,2
2
1279B,AB915,1
1279B,AB915,3
1279B,AB915,1
4
1288A,AB922,2
2



Thanks for any help,

David