Discount based on number of *unique* items

[Dojindo]

Hi!

We are looking for an application or combination of applications that will satisfy a very specific scenario, even if through a roundabout method.

We want to create a promotion with multiple items, where each unique item contributes to the overall discount. 

For example, consider a promotion that includes items A,B,C,D, and E.

Each item is individually discounted at 5% off.

Buying A and B together provides a 10% discount on both.

Buying A, B, and C all at once provides a 15% discount on all three.

Etc.

However, there are additional caveats to this:

- Only unique items should contribute to the discount (as in, buying one of A and two of B will still only provide a 10% discount)

-If possible, we would like to limit the discount (such that buying A, B, C, D, and E will still only provide 15% off).

If we need to create tiers of discounts, it's understandable. My main interest is in discount conditions that depend on the number of unique items being purchased.

Thank you!

[Derek_Morin]

@Dojindo This is how I would do it, using this app.