Discounts based on same title

Hey folks,



Has anyone been able to do this … I have tried with promotions, but what seems to happens is it applies the promotion to the total order within the cart.



What I am trying to achieve is this;



Volume discounts on orders of (x) or more of the same title. (x) being the quanity and the discount being based on percentage.



If I have say 9 copies of one title in my cart, there is no discount. But if I have 15 of another title, then there is a 5% discount on the 15, not the 9, or the combination of the two.



Any help would be appreciated.



Cheers