include/exclude part of code from web.xml file when using build.xml for build

I want to include/exclude below part of code from web.xml file when i build my web application using build.xml file.

web.xml :

      <security-constraint>
          <web-resource-collection>
                <web-resource-name>
                       Caching access BASIC protection
                </web-resource-name>
                 <url-pattern>/employee.act</url-pattern>
                 <http-method>GET</http-method>
                 <http-method>POST</http-method>
          </web-resource-collection>
          <auth-constraint>
                 <role-name>admin</role-name>
          </auth-constraint>
      </security-constraint>