Thank you for writing.
The restriction on duplicate names when adding property store items is provoked by the fact that you cannot have an actual object with two properties with the same name. Such a class/struct would not even compile.
To get two properties to display the same name you can use the Label property of each property store item. The text set to the Label property is displayed in RadPropertyGrid. You still have to use unique names for the properties, though.
I hope this will be useful. Should you have further questions, I would be glad to help.
the Telerik team