I have 10 different simple products.
If a customer buys any of 2 (among 10) then it will be 5$ price discount.
If a customer buys any of 3 (among 10) then it will be 10$ price discount.
So among 10 products on basis of Quantity user gets the discount.
Tier pricing is only used for that product. But I have to do same for X products.