2nd Level Domain Problem with Country Code

Currently I am working on a website whose domain is something like www dot mydomain dot com, now I have to create multiple subdomains with country code i.e www dot subdomain dot mydomain dot com.uk. I have linux hosting with control panelx which is allowing to create only subdomain like this www dot subdomain dot mydomain dot com but there isn't any country code.
Example sites are www dot gumtree dot com whose subdomain looks like www dot wellington dot gumtree dot co dot nz
here you can clearly see last part of the domain which become changes according to the region.

Welcome to Dev Shed.

the country code is not part of a subdomain. You need to purchase the domain name with the country code, so you would need to purchase gumtree.com.nz and then create the subdomain for wellington to create www.wellington.gumtree.com.nz

thanx for reply
but I wanted to confirm that if I have already purchased "www dot gumtree dot com" domain so then I would also need to purchase www dot gumtree dot co dot nz.

Correct.