[racket] adding other objects to custodian

At Sun, 4 Jul 2010 16:26:21 -0400, Eli Barzilay wrote:
> On Jul  4, Matthew Flatt wrote:
> > [...]
> > 
> >  * A subprocess can create any number of sub-subprocesses itself, and
> >    there's no way to kill those, which isn't very custodian-like.
> 
> Isn't a process group the way to solve this?

My impression from looking into this before was that process groups
don't help. Can't a subprocess just declare itself to be a new process
group (and there's no hierarchy)?