JIRA integrated with TeamCity continuous server through the application link. The procedure of adding an application link differs a little bit for different JIRA versions.
From 1.7.0 version the add-on supports integration with multiple TeamCity servers. For each TeamCity instance, you need to have an individual application link.
The primary application link to TeamCity server does not affect anyhow functionality or way the add-on operates with other application links. Build data from the primary application link is shown first data on the TeamCity tab.
See the next pages, for details on how to configure an application link for your JIRA version: