Discounts and promotions?

Hi everybody,
I have the following problem to solve:

Client "A" is member of the "discount group". For example he has 10% discount. But I have also some products in "promotion" on which I don`t want the client "A" to have these 10%. So if the client "A" make an order for products which are in "promotion" AND products which are not in "promotion" the shop give these 10% group discount on the total order. Is there any way the shop to calculate these 10% ONLY to the products which are not in "promotion"?

Thanks in advance.

You have to write code to make it work this way. Discounts are cumulative by default.

Thanks very much. So it comes the second question :)

Is it possible in the administration panel when you see the order of the client to see which products are in "promotion"?

Thanks