I have dynamic navigation using the Razor below, but for some reason the if statment that includes Where("Visible") is not working. These children still show up in the navigation. Suggestions?

@inherits umbraco.MacroEngines.DynamicNodeContext

@{
var StartLevel = String.IsNullOrEmpty(Parameter.startLevel) ? 4 : int.Parse(Parameter.startLevel);
var FinishLevel = String.IsNullOrEmpty(Parameter.finishLevel) ? 6 : int.Parse(Parameter.finishLevel);
var page = Model.AncestorOrSelf(StartLevel);

    if(page != null)
    {
    <h2>
        <a href="@page.url">@page.name</a>
    </h2>
    @traverse(page, StartLevel, FinishLevel);   
    }                
}   

@helper traverse(dynamic page, int StartLevel, int FinishLevel)
{
    <ul class="nodeList list-aside">
        @foreach (var node in page.Children.Where("Visible && NodeTypeAlias == \"AboutRoseLevel4Page\" || NodeTypeAlias == \"ExternalLink\" || NodeTypeAlias == \"AboutRoseVoices\" || NodeTypeAlias == \"PresidentsHomePage\" || NodeTypeAlias == \"PresidentsInternalPage\""))
            {
            var itemName = node.HasValue("shortPageTitle") ? @node.shortPageTitle : node.HasValue("pageTitle") ? @node.pageTitle : @node.pageName;
            var levelOne = node.IsAncestor(Model) ? "class=levelOne" : "";
            var childActive = node.IsEqual(Model) ? "class=activeChild" : "";
            var target = node.externalUrl ? "target=_blank" : "";
            var link = node.HasValue("externalUrl") ? node.url : node.Url;
            <li @childActive @levelOne ><a href="@link" @target>@itemName</a>
    @if(node.Children.Where("Visible && NodeTypeAlias == \"AboutRoseLevel4Page\" || NodeTypeAlias == \"ExternalLink\" || NodeTypeAlias == \"AboutRoseVoices\" || NodeTypeAlias == \"PresidentsHomePage\" || NodeTypeAlias == \"PresidentsInternalPage\"").Count() > 0 && node.IsAncestorOrSelf(Model) && node.Level <= FinishLevel)
          { 
          @traverse(node, StartLevel, FinishLevel);
          }
            </li>
          }
    </ul>     
}