Marketpress - Global Cart

Hello!

I've been looking through Marketpress for a while now and am having trouble figuring what I need to do.

I'm currently creating a website for music education teachers. This specific group of teachers are from either the US, Canada, AUS or New Zealand. What I would like to do is have a store that houses products for the US/Canada teachers in one store, in US dollars and another store for the AUS/NZ teachers in the AUS dollar. Is doing something like this possible with a multisite?

Could I have one of the stores on one site and the other one on one of the sub-domains? Is it possible to collect two different currencies from one install of marketpress if I'm using PayPal Express checkout on the multisite.

If this is all possible, how do I go about setting up the global cart? Or is that not the way to go?

Thank you for any insight!