Thanks for response. I will try the suggest approach.

In a TemplateColumn the datatype of the column is bound to the field that the key would map to.  If you want to use the full data object in your sort comparer then you would need to be an unbound column.

Otherwise, you can attach to the ColumnSorting event, look for the key of the column that you want to redirect, if you see that key add your redirected column to the SortedColumns collection and cancel the current sort action instead.