Create a Joomla menu item with menu type Community Builder > Plugin then select CB GroupJive as the plugin. Now set Action to Group and supply the groups id for the ID parameter. You should have no issues assigning modules to that menu item.
As a workaround, I thought about possibly using the About tab in the group and placing the module using {loadposition position[, style]} but embedding modules like that doesn't seem to work either in groupjive.
It's possible to do that, but you need to first enable content prepare for CB GroupJive About plugin in its plugin configuration by setting "Content Plugins" to "Enabled".