Import Senerio

Dear Gurus,

When I am doing GR system ask me the custom invoice number & I give it.but the GR quantity shows the full order quantity.My client that quantity for which Bill Of Entry had been made. How can I do that?What configuration I need to do to restrict the quantity more than BOE quantity?

EXAMPLE:

BOE quantity-5 nos

GR should not be more than 5 nos.

Padam Kumar