set price for n items in same category

Hi

Is it possible to set price for buying at least n(say 5) different items in the same category??
I notice that this feature is there for the same item.
So for example, products in category A have same price (e.g.10). So i want to make the price to be 7/pcs if the customer buy at least 5 products in category A. Products do not need to be the same. The condition is applied as long as they have 5 qty from category A.

thanks