Not sure where to go with this.

My client has a huge number of SKU&#8217;s, each of which may have a discount, depending on order quantity.
Eg 1-9, 10-49, 50-100
My initial approach was to evaluate the discount based on product category, (each category has a different level of discount ) and apply different discount bands accordingly.
One example would be

Number of Items with DiscountGroup of A >= 10
AND Number of Items with DiscountGroup of A< =49

Calculation Based on Items with a specific value,
Total of TotalPrice where DiscountGroup has a Value of A times (my variable)

This works, but in a cumulative fashion,
ie 2 separate products in discount group A, each with 6 units, will give 12 units and apply the discount.

The desired result is now to ignore the grouping for the trigger, so that each product is dealt with separately.
So that If I have 6 of Item 1 and 6 of item 2, no discount is applicable.

Hope this makes sense.
Please advise a way in to deal with this, I have a mental block.
The discount group approach works as it gives me a lot of flexibility, and with a reasonable number of discount rules, but I can&#8217;t have a different rule for every sku !!