Excess Goods Receipt?

Hi,

My Client Requirement At the time of Goods Receipt Excess quantity should be received.

Eg:- PO Quantity is 100 no's

Vendor Bought 200 no's

GRN 200 quantity system should allow. But they want only 100 to be taken remaining 100 should be kept separate(here material is subjected to Quality Inspection) if any fault in it they should take from remaining 100 quantity.

how to map it?

Regards

Shiva