Need to show discounted cross-sell products

Let’s say I have a product (Product A) where if someone selects Product A to buy, I would like to offer them a $2.50 discount each on Product B, Product C, and Product D. I am able to set-up the pricing structure through a Dynamic Pricing plug-in but I wanted a way to advertise this when they add Product A to cart. So using Boost Sales plug-in, I first tried just adding Products B, C