Teamtalk server listed as a service?

You certainly can, just don't check the "LINK" box on the advertised services and instead just the name of the service will be sent out for users to know it exists. You may want to put some details in the name (like port number if its differs from default, etc)

 

If you check with the TeamTalk people they might even have registered a URI handler that  you can use to make it a clickable link (eg websites use HTTP://  irc servers will use IRC://  there might be one for team talk) or it seems they use something called TeamTalk files (.tt) that can be uploaded to a webserver and advertised out as a hyperlink