Formula's functioning across multiple sheets - multiplier to adjust prices on other sheets

Hello,

I am creating a interactive price catelog for my company. The 1st sheet on this catelog with have list item categories that are on each of the following sheets and allow customer to input a number that will directly affect the values on the other pages.

For Example:

Sheet 1

Product Category 1 pages 1-2 ____.75_____ (multiplier)
Product 2 Page 3 _________ (multiplier)

Sheet 2

Item1 $ 2.00
Item2 $ 2.50
Item3 $ 1.25
etc.

How can i get it so all the prices on sheet 2 will change when multiplied to the value on the cover page. In this example i would want item1-3 to be multiplied by .75 that i enter on the cover page? I would like to be able to change the value on the cover page becuase we dont provide our customers the exact same discount per quote. NOTE the value's on sheets 2+... are already entered if that makes a difference.

Appreciate the help in advance!