Price Book - Prevent Items That Do Not Appear Within A Customer Price List From Being Added To A Quote/Sales Order

At present anyitems that are not included on a customers price list canbe brought though onto a Quotation/Sales Order and if there is no Standard price to default tothey will be brought in at a zero price. The idea isprevent items that are not included within the customer Price List from being chosen on the Quotation/Sales Order. This would assist business that do not usestandard prices, butdetermine prices purely on a customer by customer basis.