Amber -
Thank you for your question and the details of your use case.
Currently there aren't any plans to create a Parent / Child Relationship within the segment ID's. However, we recognize that there's room to improve and expand the way segments work in the portal reporting. We see location and technology (e.g. data center) as useful to implement as additional variables. It seems like you and other users may benefit from being able to assign your own tags/variables, such as criticality level.
In the next few weeks we'll start the evaluation of implementing these enhancements. We'll include Leena and if/when needed we'll have her or you represent more of your use case details.
Teresa