Attach existing VS.NET 2008 instance that's already debugging as JIT debugger

Is it possible to configure the VS.NET 2008 "Just-In-Time" Debugger dialog to show an existing instance of Visual Studio that's already attached to another process?

The scenario I have is an NUnit unit test that runs another process. When I'm debugging the unit test I want to automatically launch the debugger for the child process it runs as well. I pass a special parameter to the child process and the child calls Debugger.Launch(), which is all fine, but when the JIT debug dialog comes up it doesn't list the existing VS.NET instance - I can only open a new instance, which is quite inconvenient.

From stackoverflow

• A debugger that's attached to another process, cannot attach to a secondary process. I think it is possible to have a debugger attached to multiple programs (you can debug multiple websites that are part of the same solution for instance).
  Also, you cannot attach more than a single debugger to each process.

  Evgeny : Thanks, but VS.NET CAN debug multiple processes if you go through the Debug, Attach dialog. It just seems that it can't do that through the JIT debug dialog for some reason.