AP Invoice Hold Question in R12

 Hi,
that might be a basic hold question for more advanced ap users.

In R12, is it possible to put a hold on the  ap invoice if invoice price is less than the PO price? To be more specific:
1) Create a PO with qty 2 and price 100
2) Receive PO
3) Enter an Invoice with price 80 and qty 2, match to PO generated in step 1
4) Validate the invoice, no hold is placed.

Is there any standard functionality that will hold the ap invoice in step 4?

thanks in advance;