Having Discount Apply to Products Only, NOT ADD-ONs

[corpdrives]

Is there any easy way to setup prestashop to give a discount for the products but not the add-ons that incur additional costs?

For instance, i have a product that I'm offering RUSH SERVICE for. Rush Service costs $2 per unit extra. If a client orders 1000 products, they get a 50% discount. Unfortunately, that discount applies to Rush Service costs too, so they are getting charged $1 per unit instead of $2. Is there anyway to isolate the product so only the quantity gets a discounted price, yet they still pay the full cost of $2 for Rush Service instead of getting charged a discounted $1 per unit?

Thanks in advance for all your support. I'm really enjoying this Prestashop group, your product and your forums.