Canvasmm Group question

Folks,

Is there a way of clearing out the contents of a Canvasmm? In general
you can delete a group, but the root group is protected against this.

For that matter, does Canvasmm allow the child items in a group to be
retrieved?

Thanks in advance,

Nick Glencross

(I'm assuming that libgnomecanvasmm questions should come here, and not
to gtkmm)