Automatic price adjustment based on material quality

Hi Gurus,

Please throw some light on following scenario.

X material will be received in batches, and that material will subject to Quality Inspection. (QM is activated)

While doing GR for this material, in inspection it has been found that the material quality is poor. As the requirement is critical, we want to accept that material.

But as we received inferior quality material, we want to pay less price to vendor, than agreed price. 

Can it be managed automatically by the system? If so, what is the procedure, or configuration part to be followed?

Regards,
Naresh