Form authentcation with user roles problem

I have Use Repeater for my sitre nevigation with sitemap daya source
<asp:Repeater ID="NavigationLinks" runat="server" DataSourceID="NavigationSiteMap" EnableViewState="false"> <ItemTemplate> <asp:HyperLink ID="NavigationLink" runat="server" Text='<%# Eval("Title") %>' NavigateUrl='<%# Eval("Url") %>' EnableViewState="false" /><br /> </ItemTemplate> </asp:Repeater> <asp:SiteMapDataSource ID="NavigationSiteMap" runat="server" SiteMapProvider="NavigationSiteMap" ShowStartingNode="false" />



but my site has 3 user type emp ...