how do i apply discount ONLY if at least X number of DIFFERENT sku's in cart share same attribute in magento ? for example, if i have 3 different products in the cart (different sku) with a custom "material" attribute set to "aluminium" then will apply discount, BUT if there is only one product sku with a "material" attribute set to "aluminium" in the cart, and the quantity of that product is set to 3, in that case discount will not apply since there are not 3 different sku with a "material" attribute set to "aluminium", each sku needs to be counted only once
i hope that makes sense.. thanks:) magento 1.9
