Hide Sitemap items without Role based authentication

I am wondering if there is a way to hide items on my menu without role based authentication.  We switched over to using sitemaps with our menus but now we are running into the problem of needing to hide menus from users, but do not want to fully go down the road of role base authentication since we do not use forms authentication but windows authentication.  Is there a way to do this or do we need to go back to old way of populating the menu statically instead of from
<telerik:RadSiteMapDataSource ID="SitemapData" runat="server" SiteMapFile="Web.sitemap" ShowStartingNode="false" /> <div id="dvMenuWrapper"> <telerik:RadMenu ID="radMenu" runat="server" Skin="Outlook" ExpandAnimation-Duration="250" CollapseAnimation-Duration="250" Width="100%" style="z-index: 6250" DataSource ...