Yes, you can add object parenting between two or more subjects.
To do so:
- Hover over the annotation and press the "hierarchy" icon.
- When pressed a link icon will turn on for all other compatible annotations.
- The selected link will become the parent annotation of the child object, and the child’s hierarchy icon will turn yellow once connected.
You can also join parenting on selected:
- select all annotations in the annotations list by using Ctrl+left mouse click (Children and Parent).
- Press "Join Parenting on Selected".
- Press the Parent to create the hierarchy.
For more information please go to Object Parenting.