C# :: How To Allow TreeView To Have Child Nodes Of Different UI Types

Right now I'm working on a TreeView for which I would like to add a TextBlock and a ComboBox as child nodes of a Parent TextBlock node. This would look something like this:

My TreeView is implemented using an MVVM style, and utilizes a HierarchicalDataTemplate. I have had no problems with adding TextBlock nodes and TextBlock children, but the confusion seems to arise when adding child nodes of different UI types.

I have tried implementing a stackPanel, like so:

<HierarchicalDataTemplate DataType="{x:Type Data:Node}" ItemsSource="{Binding Teams}">
<StackPanel>
<TextBlock Text="{Binding IndividualProperty}" />
<ComboBox ItemsSource="{Binding CollectionProperty}" />
</StackPanel>
</HierarchicalDataTemplate>

But then I end up with each node looking like this. It's like each node comes with one TextBlock and a ComboBox (Note: The comboBox is not the child, it and the TextBlock are one node):

How do I allow my treeView to have child nodes of different UI types? I am thinking that my solution has to do with my Hierarchical Data Template.