How to create many Tags in one tag using webcontrol in asp.n

Question

Hi.
I want to create a custom webcontrol with result like below:

<myControls:MyGraph id="myGraph1" runat="server">
  <Colors>
    <myControls:ColorD Value="#abcdef" />
    <myControls:Color>  Blue </myControls:Color>
    <myControls:ColorD Value="#1ad234" />
    <myControls:ColorD Value="#123456" />
  </Colors>
</myControls:MyGraph>

and I want to know the order of them too.May someone help me about this?

Thanks and best regards,
Nguyen DC