Condition formula for condition type

Hi

I need help to create a Condition formula for alternative calculation type in my sales order, I want to link to my condition price a formula:

The aim of the formula is to give a price accordind the global quantity  of the sales order, for instance :

I have several times the sames material :

Line 10      MATERIAL X               QTY 50000

Line 20      MATERIAL X               QTY 10000

The price must be calculated according the quantity global  and the scale of the condition time :

Material X  0 to 60 0000 the price is 1000£

So the price of my sales order must be 1000£

Any body could help me to do this formula?

Thanks a lot

Regards

Kari