Unfortunately there is no such direct thing.
The KAH3 order groups themselves are not authorization relevant.
You can however add your vote to http://scn.sap.com/thread=3298966 if you want a standard solution and have lots of patience (as you can see, SAP turned it down for me at the time and told me to go and talk to a wall... :-)), or alternately you can contact me as we were forced to build our own solution as a result to calculate the orders of the group and authorize them individually or in groups or along the lines of cost centers or cost center groups.
Cheers,
Julius