Determine the Number of total records (e.g. schedule lines) each Data record per BW Routine

Hi experts,

I would like to set the number of total schedule lines of a Document Number and Document Item combination.

For example:

Doc. Number 262 item 10 with in total 4 schedule lines. So I would like to set the Number of schedule lines each data record.

Background: I would like to know how many schedule lines each sales doc. item are exist.

Any ideas how to implement this over a BW Routine (e.g. in the end routine)?

Many thanks in advance!

Best regards,

Michael