I'm not sure if it works the same way on the iSeries, but in the Multiplatforms world, this is fairly straightforward:
You can retrieve a loaded file using the "arsdoc get" command -- specifically, use the -X option and specify the load ID in order to get the actual document back.
Once you have the data extracted, you can reload it into the new Application Group with arsload.
You can find the complete documentation for arsdoc in the Administrator's Guide. (For CMOD Multiplatforms v8.4.1 -- it starts on page 245.)
Hope this helps!
-JD.