Disallow New Sales Orders for Customers w/ Bad Credit

Ok, so I want to create a custom field on customer records that tells whether a customer is on credit hold and whether they should be allowed to make any further purchases. I know I can make a simple custom check box or "yes" or "no" drop down field in the customer record that indicates their credit standing but there's a kicker. If the check box is checked, or the drop down is set to "yes," indicating they are not in good credit standing, I need NetSuite to disallow the creation of Sales Orders for that customer until the checkbox