Enquiry on Target Based Discount

[JakeLeong]

Hi all, @All 

I would like to create a target based discount for a collection of products. 

Example: Total products in the collection is 99. When is sold for 33 products, the following buyers can get 10% discount and when is sold for 66, then the following buyers can get 15% discount. This discount will be applied for a combination of customers and there will be a notification bar on top of the website showing the existing quantity and target left to achieve the following discount rate.

How do I do so, is there any app that allow me to do so?