74967 OsCommerce modification

I need a modification for the OsCommerce script. I need to be able to set a minimum QUANTITY order fo certain products and if they order the product and they do not order the minimum it does not let them order. It has to be able to be set for some items but not all and it might even been different quanties for different items. so for example: Item A - no minimum quantity Item B- must order 10 Item C - must order 7 Item D- no minimum order Item E- must order 5 etc, etc.