Shipping From Two Locations For Some Orders

Here's my dilemma:
My company (http://www.beerdolier.com) just setup an Australian distributor. While we have about 15 colors available in the non-Australian markets (i.e., everything shipping from our Louisville, KY location), we only have 4 selections available to ship locally in Australia. Because the marketing for the US market doesn't resonate with the Australian market all that well, we are setting up a second cart at http://au.beerdolier.com (still working on doing the Multi-Site Module, otherwise it'll be a stand-alone).

So what we've decided to do is not limit Australian customers to only the four colors, but if they choose a different color, it will have to ship from Louisville, KY. I want to be able to remove Australia from the available Countries on our "everyone else" site to avoid confusion, directing all Aussie-based customers to head over to our local Australian distributor.

So basically, is there a way to tell Zen Cart "These four products ship from this location and the rest of them ship from this other location." We'd have to charge them for two different shipments.

Here's an example:

• Australian customer orders 1 Black (available locally), 1 Red (available locally), and 1 Black/Yellow (available to ship only from Louisville).
• We'd want to charge them for Aussie-based shipping for the black and red ones.
• We'd want to allow them to select their USPS shipping style for those coming from the US.

Can I do something like this? Or perhaps there's a way to increase the shipping price for the non-locally available options, so that it just increases the Aussie-based shipping price, we give them a heads-up that certain items are coming from the US, and we use the extra to ship it via USPS?