TransformGroup group = new TransformGroup( );
Shape3D shape0 = new Shape3D( geom0, app0 );
Shape3D shape1 = new Shape3D( geom1, app1 );
. . .
SharedGroup shared = new SharedGroup( );
shared.addChild( shape0 );
shared.addChild( shape1 );
shared.compile( );
. . .
Link link = new Link( shared );
. . .
group.addChild( link );