Best pratice for Cart discount, Attributes and Configurable Products

[TONZR]

Hi,

I will try and explain myself as good as I can.

I have 1 configurable product where you can pick it with or without purfume and also which amount that you what etc. 50ml 250ml and 1000ml

Heres the issue - On the webshop there is a cart price rule where if you buy 3 products you get 30% discount but the discount also applies to 50ml and 1000ml but it should only apply to the 250ml.

I have tried making a new category for the 1000ml and 50ml and then add a "does not contain" rule for the cart discount so it should not apply the discount but it is not working it still adding the discount.

Is it making any sense?

Is there an solution for this or should I make a product for each amount or whats the best way to solve this?

[Tom Robertshaw]

What attribute is the 250ml, 1000ml values in? Could you edit that attribute to say that it's available for use in promo rules and then update the condition to use that attribute instead of category?