Groups which have been saved out of Revit and placed into Vault, can not then be Loaded as a Group into a future Revit project. There is no integration supporting this architectural workflow.
Currently a workaround is required to download the group file out of Vault first and then use the regular 'Load as Group'. This slows down an otherwise fast process which Revit users have been enjoying for years.
We need better integration of Revit into Vault. This is yet another example of why Vault for AEC is not ready for the AEC market. There are plenty of small holes in the integration which need to be addressed first.