RadGridView does not suppport merged cells behavior, however you may easily emulate is using the approach demonstrated in the following blog post. Regarding to the columns and the internal logic of the application you may use our built-in GridViewCheckBoxColumn or to define your custom column with a single checkbox in it, please refer to the following article. Once specified you may bind the CheckBox's IsChecked property to the property value of your underlying business object that holds the information about the relation between Country and State. Furthermore you may enumerate the States in the same way as it was implemented at the following online demo.
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