Is there really much point for forming groups if group members can't communicate within their group? Not really.
Other group forming components include very basic discussion functionality natively rather than as an integration (ie - JomSocial).
It may be in GroupJive's best interest over the long term to include such functionality natively as well rather than wait for greater certainty among Joomla forum components.
There's some discussion of this here:
www.groupjive.org/index.php?option=com_k...atid=224&id=6398