WPF - DataTemplate to show only one hierarchical level in recursive data

Question

Hi all,
I am using a tree to display my data: persons grouped by their teams. In my model a team can contain another team, so the recursion.

I want do display details about the selected node of the tree using a contentpresenter. If the selection is a person, everything is fine: I can show the person name or datails without problem using a simple datatemplate. If the selection is a team I would like to display the team name followed by a list of member names. If one of these members is another team I would like to display just the team name, without recursion...

My code here is wrong because it displays data in a recursive way, what is the right way of doing it?

Thanks in advance for any help!
best regards,
Paolo

<ContentPresenter Content="{Binding Path=SelectedItem, ElementName=PeopleTree}" >
    <ContentPresenter.Resources>

        <DataTemplate DataType="{x:Type my:PersonViewModel}">
            <TextBlock Text="{Binding PersonName}"/>
        </DataTemplate>

        <DataTemplate DataType="{x:Type my:TeamViewModel}">
             <StackPanel>
                 <TextBlock Text="{Binding TeamName}" />
                 <ListBox ItemsSource="{Binding Members}" />
             </StackPanel>
         </DataTemplate>

    </ContentPresenter.Resources>
</ContentPresenter>