Lineup Box: merge cells ?

[#1]

For a lineup box, is it possible to add an entry which spans across multiple "cells"?

to get this design:

instead of this one:

pb = Expr(
	Panel Box( "", Spacer Box( Size( 20, 20 ) ), <<background color( "dark blue" ) )
);
sb = Expr(
	Spacer Box( Size( 20, 20 ) )
);

New Window( "test design",
	Lineup Box( N Col( 4 ), 
	pb, pb, pb, pb, 
	pb, pb, pb, pb, 
	pb, sb, sb, pb, 
	pb, pb, pb, pb, )

);

[#2]

You can use Unlineup Box but the spacer box(es) inside that will require some tinkering

[#3]

nice : )

The issue with unlineup box(): It spans along all columns.
How can I guarantee that the cells in the last column line up correctly?

[#4]

I set the spacing for the Lineup Box and added a margin to the right side of the wide Spacer Box in the Unlineup Box with an H List Box.

pb = Expr(
	Panel Box( "", Spacer Box( Size( 20, 20 ) ), <<Background Color( "dark blue" ) )
);
sb = Expr(
	Panel Box( "", Spacer Box( Size( 20, 20 ) ) )
);

New Window( "test design",
	Lineup Box( N Col( 4 ), Spacing( 5 ),
		pb, pb, pb, pb,
		pb, pb, pb, pb,
		Unlineup Box( H List Box( Panel Box( "", Spacer Box( Size( , 20 ) ), <<Background Color( "dark blue" ), <<Margin( Right( 5 ) ) ), pb ) ),
		pb, pb, pb, pb
	)
);