Align controls' sizes

Question

Simplified problem.

I have two ItemsControls that are located one under another and are bound to the same sequence:

[Control] [Another Control] [More Controls]
[Other Ctrl] [Super Control] [Control]

What I would like to do is align their sizes such that they appear to be a single table:

[Control   ] [Another Control] [More Controls]
[Other Ctrl] [Super Control  ] [Control      ]

It would also be acceptable to go "one-way": make bottom items same size as top ones, even if they are shorter:

[Control] [Another Control] [More Controls]
[Other C] [Super Control  ] [Control      ]

A few considerations:

1. Yes, they have to be in separate ItemControls.
2. No, I cannot use Grid or DataGrid.
3. I fully own the back-end data structures (if that helps)

For a more complete explanation, one can refer to my other question.

UPDATE: Why do they have to be in different ItemControls
In general, what I'm trying to achieve is to build a table that is bound to a rectangular data structure. I do not see any way to do this other than using nested ItemControls: one ItemControl for rows, each item containing another ItemControl for cells in that row. Or vice versa: one for columns, each item containing cells in that column. Either way, nested items will have to be aligned to each other.
I do realize that there may be other way to create such a table that I do not see. Which is why I also asked the other question.

Thank you, oh almighty community, in advance.

Answer 1

Try the following:

 <StackPanel Grid.IsSharedSizeScope="True">
    <StackPanel.Resources>
        <DataTemplate x:Key="SharedSizeTemplate">
            <Grid>
                <Grid.ColumnDefinitions>
                    <ColumnDefinition Width="Auto" SharedSizeGroup="SharedSize"/>
                </Grid.ColumnDefinitions>
                <TextBlock Text="{Binding}"/>
            </Grid>
        </DataTemplate>
    </StackPanel.Resources>
    <ItemsControl ItemTemplate="{StaticResource SharedSizeTemplate}">
        <ItemsControl.ItemsPanel>
            <ItemsPanelTemplate>
                <VirtualizingStackPanel Orientation="Horizontal"/>
            </ItemsPanelTemplate>
        </ItemsControl.ItemsPanel>
        <System:String>One</System:String>
        <System:String>Longer</System:String>
        <System:String>Longest</System:String>
        <System:String>Very Longest</System:String>
    </ItemsControl>
    <ItemsControl ItemTemplate="{StaticResource SharedSizeTemplate}">
        <ItemsControl.ItemsPanel>
            <ItemsPanelTemplate>
                <VirtualizingStackPanel Orientation="Horizontal"/>
            </ItemsPanelTemplate>
        </ItemsControl.ItemsPanel>
        <System:String>Short</System:String>
        <System:String>S</System:String>
        <System:String>Even longer than above</System:String>
        <System:String>V</System:String>
    </ItemsControl>
</StackPanel>

EDIT: There is still one problem though - all columns will be sized to the same optimum width - don't know if you can live with that?