Reduction of Samples from all SUs

Dear QM experts,

A goods receipt is done for , say 5 Containers each with a SU number (Warehouse Management is active).

The samples are drawn one each from each of the containers

After Usage decision ,Posting to Sample usage is carried out.

In the Transfer Order that is created and confirmed automatically, system reduces the entire Sample quantity from the first SU number.

How can we make the system reduce the quantity from each of the SU numbers as physically one sample will be taken from each SUs.

Regards,

Sudhakar