Attributes Qty Price Discount

Hi Everyone,

Here is my problem.

For 8 x 10 x 1 case ( 30 presentation boxes) I charge, using Attributes Qty Price Discount feature, following 1:18.00,2:11.00,3:9.00,4:8.00,5:7.50 for imprint.

It means that I charge $ 18.00 to imprint 1 case, $ 22.00 to imprint 2 cases, $ 27.00 to imprint 3 cases etc.

For 8 x 10 x 1/2 case ( 50 presentation boxes) I charge following 1:20.00,2:14.00,3:12.00,4:11.50,5:10.50 for imprint.

It means that I charge $ 20.00 to imprint 1 case, $ 28.00 to imprint 2 cases, $ 36.00 to imprint 3 cases etc.

So, if somebody orders 1 case of 8 x 10 x 1 boxes and 1 case of 8 x 10 x 1/2 boxes that person is charged ( $ 18.00 + $ 20.00) $ 38.00.

Question: If somebody orders 1 case of 8 x 10 x 1 and 1 case of 8 x 10 x 1/2 boxes can setup be done so it charges 1 time $ 11.00 for 8 x 10 x 1 and 1 time $ 14.00 for 8 x 10 x 1/2 boxes. Total: $ 25.00 ?

In another words, my setup works as long as somebody orders one or more than 1 case from the same product page. If somebody orders more than one case (different sizes) from 2 or 3 product pages he/she is charged as ordered 1 individual case each time.

here is a link:

http://www.ricestudiosupplies.com/photography-presentation-boxes/black-glossy-boxes/8-x-10-black-glossy-boxes

Is there any/other way to solve this ?

Thanks in advance.