R. Sgr,
Seems like your requirements are meandering a bit. First you talk about STOs and POs, now you are talking about Scheduling agreements. It is a bit hard to follow.....
Your scenario is somewhat bizarre. It appears that you have configured your Scheduling Agreements to replenish the warehouse such that they are planned with multiple schedule lines, but you don't want to deliver to the warehouse according to the multiple schedule lines. This doesn't sound like a problem with VL10B, this sounds like a problem with your Scheduling agreements. Why have you created them in this way? Don't you think these SAs should use aggregation horizons to combine schedules?
Anyhow, if you insist on butchering VL10B, then I believe the question has been answered, by using the note mentioned by various experts above as a basis for your programmers.
Best Regards,
DB49