BoundingBox

You can provide element in options.boundingBox to limit crossing element borders.

This items cannot cross its example element, just try it your selves.

Item 2.

Item 3.

Item 6.

This items cannot cross its example element, just try it your selves.

Item 4.

Item 5.

        
  dragularService([$element.children(), {
    boundingBox: $element
  });