Hello Casey ,
Please see the sample attached. It is a modified version of the previous project with a few lines of c# added. I believe it gets us closer to the goal .
Here is the relevant code:
|void RadGridView1_Grouping(object sender, Telerik.Windows.Controls.GridView.GridView.GridViewGroupingEventArgs e)
| if ( e.GroupDescriptor.Member == "GroupID")
| e.GroupDescriptor.AggregateFunctions.Add(new CountFunction("count","GroupID","place custom caption here"));
This tells the RadGridView to add aggregate results in the group headers when the group is by "GroupID".
* To see this in action , just group by GroupID and then by Age ( don't use the buttons ).
Let me know if I can help further.
the Telerik team