Why focus just on Norwegians? You might want to market to a broader segment of people who'd like a home in Thailand. And do you mean people who are living in Norway. That's OK, though very narrow. If you mean people of Norwegian descent living in the United States, don't do that. Don't limit your target group to one ethnicity or country of origin.
I'm guessing the property in Thailand would be a second home, a resort-type home. If so--beginning with Norwegians living in Norway--do market research on how Norwegians select places they want to vacation or live. Find out the demographics of those most likely to buy a property halfway around the world. Then target your marketing and advertising to them.