Referring to parent environment variable

I would like to have a hierarchy of environments with a key named path that would, at the root level have the base URL, while descendants' environments would add parts to the path

For example, a hierarchy of environments:
• root:"path": "
• child:"path": "{parent.path}/api"
• grandchild: "path": "{parent.path}/v1"

Would resolve to " " and " in the root, child and grandchild environment respectively.