Here we are merging two column value in one column which have a header name Country
<asp:TemplateField HeaderText="Country">
<ItemTemplate>
<asp:Label ID="Label1" runat="server" Text='<%#Eval("CountryGroup1")+ " " + Eval("CountryGroup2")%>' ></asp:Label>
</ItemTemplate>
</asp:TemplateField>
Thanks Hope it will be useful