As far as I know, there's no such functionality in ISO-32000-1. The best chance at finding a way to do this, is by looking at the JavaScript specification.
Incidentally, I have a copy of the unpublished ISO spec "ECMAScript for PDF" (currently in development at the ISO meeting in Pretoria). This is what it says:
launchURL — Launches a URL in a browser window.
Parameters:
- cURL — A string that specifies the URL to launch.
- bNewFrame — (optional) If
true
, this method launches the URL in a new window of the browser application. The default isfalse
.
I think it's safe to say that you're asking for something that is impossible. If it were possible, the spec would mention an extra parameter to define the name of the tab or window.
(This answer isn't limited to iText; what you're trying isn't possible in general.)