This is a one line recipe to allow buildout users to refer to ${grp:GROUP} to obtain the current user's UNIX group id. In other words, the results of:
$ id -g -n
on UNIX systems, for the user executing the buildout. This can be used with gocept.recipe.env to configure ownership of the buildout directory, e.g.:
$ chown -R ${env:USER}:${grp:GROUP} ${buildout:directory}