Allow product from one blog to be sold on another blog, and commision to be paid.

Hi

Say I want to sell the following products:

1,2,3,4,5 on blog A
6,7,8,9,10 on blog B
11,12,13,14,15 on blog C

So now I want blog C to also sell product 3, and receive a commission on that sale. Product 3 should appear on blog C as if it's actually part of blog C, and not just appear as a link to blog A.

How would I do this?