Shopware.com specialist make flag selection no follow

Hello, Its about the [login to view URL] website, its edition 3. There 3 websites .de / .at / .nl and they are connected with a flag selection. My agency say its not possible to make the flag selection no follow, but only whole site no follow And that the update 4 and 5 will overwrite this. So i need a specialist who can write a code or create that for me that the flags have a no follow tag to other countries / domains.