Cannot assign a Group User through workflow

The documentation for 6.5 says: Examples of uses for a Group User would be to assign all new leads to a  group user named "Sales".

However, in Version 7.x the documentation no longer mentions this use.  It is still possible to manually assign a record to "Sales" but not through Workflow.  Group users do not appear in the dropdown list for Assigned User in Workflow.

Is this one of the features that was dropped in Version 7 or just a bug?

Thanks
Gail Darling
W-Systems Corp.