I sell a variety of products on my website and most can be shipped via USPS. Some however can ONLY be shipped by UPS/FedEx/DHL Ground service because they are aerosols. My question is this- is there an addon/contribution that would force the customer to choose ground service if they order an item that must be shipped by ground service? I'm having a real problem with customers not choosing the correct shipping option because the majority do not read the notice at the bottom of the product descriptions. This would be an enormous help if anyone can point me to the addon (if there is one). I found 1 but it does not work at all. Thanks.