In design it's possible to define a hierarchy of risks (eg. risk X consits of risk X.1 and risk X.2).
ARCM does not support this concept.
If it would be added, the principle is that a risk assessment would be done only on the lower level risks and rolled-up to the higher level.
Several customers and in several RFPs we receive this requirement.
Currently we solve this via the design and implementing the hierarchy logic in dashboards