Hi Barb,
GV acting on your SA or IC data could definitely produce this info. In fact, depending on the complexity of your new Report Group (RG) assignments, it would most likely be possible to not just identify the invoice counts but the view could also have the intelligence to display the new RG that should be assigned based on your logic for doing so. The view could be designed so that both the item(s) and the period could be selected by the user at run-time.
To automatically have the new RG assigned in IC would require the GV-RW module or some other means of writing directly to the Adagio IC database but "near automation" could be achieved by exporting the GV list and subsequently importing it into IC for the update.
In my opinion exactly how to do this falls outside the scope/purpose of this forum and I would recommend you contact your Adagio consultant so that he/she can assist you with the solution.
Regards, Pete