Use Generic GroupDescriptor

This help article will show you how to create generic expression GroupDescriptors for RadGridView.

Generic GroupDescriptor

You can also group objects by the result of an equally complex operation:

Example 1: Create a generic GroupDescriptor.

var descriptor = new GroupDescriptor<Employee, int, int> 
{ 
    GroupingExpression = e => e.Orders.Where(o => o.Details.Any(d => d.Product.ProductName.Contains("Syrup"))).Count(), 
    SortDirection = ListSortDirection.Ascending 
}; 

For more information you can check the Grouping section.