How could I combine product discount with order discount automatically

Shopify Plus
1

Hi

Here is what I am trying to achieve:

  1. In collection/product pages, display RRP and promotion prices so customers can see how much they are saving. Let’s save total product discounts are $80

  2. In shopping cart page, if there’s order level discount $100, system automatically figure out $100 order discount is the higher than $80 product discount

  3. In this case, shopping cart only opt to checkout with $100 discount, rather than giving both products discount($80) and order discount($100)

How am I supposed to do that? Couldn’t find any app can do this use case.