You are mixing up the terms country (whereabouts) and nationality which are different things. TeamSpeak does not and cannot display your nationality. Recently, I was on holiday in Jordan, but while I was there, I was still a German national, though TeamSpeak displayed the flag of Jordan. If you communicate with people who judge you depending on your where you currently are, you should question who you play with.
(It's more of a problem that TeamSpeak saves the original IP addresses, which is not allowed in Germany. But even with the anonymization required (usually considered to be CIDR/23), it would be enough to identify a country. I don't know if this anonymization is required for connected clients anyway, which are the only one for whom a country is displayed in TeamSpeak.)

What you want is impossible anyway. It would require that people update their servers. Many people I know haven't done that in the past 4 years, so I'm sure they won't update for something that doesn't give them any advantage at all.