Yes, it is possible to use a country specific domain name on your hosting account with Siteground. For this purpose follow these steps:

1. Change the DNS servers for the domain in question at your registrar to the ones for your account. You can find the ones for your account from your Customer's arae, My account, Manage - next to your hosting account.
2. Wait 24 hours for the above changes to propagate and take effect.
3. Configure your account to use your new domain. For more information on the available options check this link.