Pay Pal Chain Payments with marketpress shopping cart plugin

Hey guys,

I have just purchased the market press plugin, I am not a super guru at php but I know my way around, hopefully this won't require too in depth php programming.

What I want to do is assign a custom value to each product in my store, this value is going to be my profit for selling that particular item.

When the customer goes through the checkout and pays, all of the items in the cart's custom values are added to total my share of profits. This is then fed into paypals chain payment system so when the customer pays, my profit gets split from the main payment and gets sent to me and the rest gets sent to my supplier with the order.

Is this going to be a nightmare, is there any documentation or guides on how to do this with market press, is it even possible.

Thanks - Dale