ASN qty check with PO qty

Hi,

My requirement is as follows:

PO is created for 100 EA.  Now I dont want to receive ASN with quantity more than 100. i.e. I dont want the inbound delivery to be created if the ASN quantity is different from PO quantity. (supplier is on portal .

How can I achieve this ?

PO is done at ECC

ASN is at portal

Thanks in Advance,