Help Shipping price for magazine volumes

[zag-rox]

Hi guys
In my store I want to add new section to sell Magazine volumes with an option that shoppers can add quantity as their requested volumes "Like adding 6 in quantity means 6 volumes order for next 6 months"
The question is how it's possible to calculate separated shipping prices for next months in checkout for a specific product?
because as you know we have to ship each month one volume of magazine to them.

I need a way to calculating like 6 different shipping prices for a 6 number of a magazine order in first order checkout!!?
Please help if you know any solution or related plugin which has option to do this!

Thanks in advance for your comments

Mod edit:  bump message removed. Please read http://forum.virtuemart.net/index.php?topic=104795.0