From the Table view in an ArcGIS Online Group, allow admin to select multiple items and batch-update sharing capabilities (same as what can be done from the Content). This would be a quick way of moving a series of items from one group to another.
Content:
![](/legacyfs/online/436023_pastedImage_4.png)
VS
Group:
![](/legacyfs/online/436022_pastedImage_2.png)