Can I have multiple unit costs on one field dependent on quantity of product selcted?

Hi,

I was wondering if the following were possible?

The Scenario:

My user is looking to have a book made and have a choice between a paperback and hardback book. For example purposes I'll use only two options to select.

- They select hardback book The total cost of this field will be dependent on how many hardback books they choose 

They select 5 books

Quantity Hardback Books (I don't want these options visible though.. this makes up the total calculation at the end) 

 1 - 10 (unit cost is 50 per book) They fall into this band

10 - 20 (unit cost is 40 per book)

30 - 40 (unit cost is 30 per book)

40 - 50 (unit cost is 20 per book)

So hardback field is = 50

They then select size A4 number of pages 700

Page Count

 1 - 500 (unit cost for page count  0.5 )

501 - 2000 (unit cost for page count 0.4 ) They fall into this band

2001 - 5000 (unit cost for page count  0.3)

5001 - 10000 (unit cost for page count  0.2)

So the calculation of this field is equal to number of pages (700) x Quantity of books (5) x unit cost (0.4) = 1400

When they press calculate at the end of the form the total would be equal to

HardbackBook Field (50)  + Page Count Field (1400) = 1450