Top Categories

I want render only specific product, see the example.

CATEGORIES:
> 4 wheels
>>> Cars
> 2 wheels
>>> MotorCycle
>>> Bike

I have Products Simple and Products Grouped in each category.
I want to show only the simple products that belong to the specific category "2 wheels" and show only grouped products that belong to the specific category "4 wheels".

I use this code to check simple /grouped products

@foreach (var product in Model.Products)
{
    if (product.ProductType == Nop.Core.Domain.Catalog.ProductType.SimpleProduct)
    {
        <div class="col-md-2 col-sm-6 col-xs-12">
            <div class="item-box">
                @Html.Partial("_ProductBox.B2B", product)
             </div>
        </div>
    }
}

But I don't know how to recover first level of category ("2 wheels" or "4 whhels")
In Model.Name I read only second level of category "Cars" or "Bike" ...
In Model.CategoryBreadcrumb.Count I have always  the value 0 ...

Where I can read the current top level of the category selected?
thanks