Desktop using master pages

How dynamically load pages in Desktop scenario using MasterPages
For Example

Code:

---

<form id="form1" runat="server">
    <ext:ResourceManager runat="server" ID="rs">
    </ext:ResourceManager>
    <ext:Desktop ID="MyDesktop" runat="server" BackgroundColor="Black" ShortcutTextColor="White">
        <StartButton Text="Start" IconCls="start-button"/>
        <Content>
            <asp:ContentPlaceHolder ID="ContentPlaceHolder1" runat="server">
            </asp:ContentPlaceHolder >
        </Content>
        <Modules>
            <ext:DesktopModule ModuleID="DesktopModule1" WindowID="winCustomer" AutoRun="true" >
                <Launcher ID="Launcher1" runat="server" Text="Add Customer" Icon="Add" />
            </ext:DesktopModule>
            <ext:DesktopModule ModuleID="DesktopModule2" WindowID="window2" AutoRun="true" >
                <Launcher ID="Launcher2" runat="server" Text="Add Customer" Icon="Add"  />
               
            </ext:DesktopModule>
        </Modules>
        <Shortcuts>
            <ext:DesktopShortcut ModuleID="DesktopModule1" Text="test" IconCls="shortcut-icon icon-user48"  />
        </Shortcuts>
    </ext:Desktop>
    </form>

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if Lets say that the "winCustomer" is situated in webForm1.apsx and "window2 " and WebForm2.aspx
and I want them load conditionally.Hou should I do it