Preventing MP from tracking a subsite

Is there a way, perhaps a code snippet that I could deploy as a mu-plugin that will force MarketPress not to track a particular subsite and not display its products in the network-wide marketplace?

I have a vendor on my network based in Australia who is going to be setting up additional sites for his distributions in the US and the UK. Because of the way currencies and shipping is going to be handled (he has a local distributor in each country) we are going to give him a cloned site for each country and the products are generally going to be the same as those in Australia. The big changes are unique pricing and shipping cost structures for the foreign distributions.

However, because the products are the same on each site, I don't want his products showing up in the marketplace three times. I'm thinking that I just want one of his sites showing up in the marketplace (the sites themselves interlink very well for the different countries so visitors can find the one for their country). I know that I can prevent them from showing up using privacy settings, but that is a kill all option, that prevents buddypress and the search engines from seeing the site. I just want MarketPress to ignore the extra sites and not track them in the marketplace.

Any ideas?