You can use the "Grouped" option on the Col List Box.
Names Default To Here( 1 );
dt = Open( "$SAMPLE_DAA/semiconductor capability.jmp" );
New Window( "Col List Box Example",
Col List Box( all, width( 250 ), maxSelected( 1 ), grouped ),
fontobj = lb = Col List Box()
);
It is documented in the Scripting Index
Jim