All products is available on the new created market

Hi guys, 

I have recently created a new market for a Episerver commerce site. It seems Episerver Commerce automatically set EVERY product is available in this new market.

Is it any setting in commerce that can change this?

I am thinking to create a job to clear all markets (use MarketFilter) before I run the product import job every time when I create a new market. But this seems not a good solution. 

Do you guys have better suggestions? 

Thanks, 

ChiChing