This sounds like a great idea in theory, but at least on 6.1 I can't get it to function.
I create an advertised huntgroup with no users "Park 1" let's say and then a Group button on the user phones for the Park 1 group.
Group is created with queuing turned on and a limit of one user in queue. No announcements, no members. All other settings are the default.
I can manually transfer a call to the new huntgroup and the test caller hears ringing (I'd rather they hear hold music), however the group button never lights with either call alerting or call queued as per the group button suggests in the docs.
Per docs, call should be considered queued if there are more calls waiting than available group members, so it should follow that with no group members, the call always ends up in the queue status and would show with that indicator. However, that's not the case--at least not on my 5420 phone.
If I press the Park 1 button on the phone I created, I'm connected to the user, but there's no visual indication that a call was in that group and queued. Am I missing something?