because of the underlying data structure and how the inheritance feature is implemented at the moment, there's no easy way to do what you ask for. Also, inheriting individual properties is currently not available because all the custom properties are actually stored in a single "document property".
In any case, we do have plans to do a major redesign and have a couple of things on board which would make your life easier in these situations. Unfortunately I can't really talk about that as this is still very early in our development phase.
Thanks Stefan. Nothing here is overly limiting to us, but enhancements to custom properties would be very welcome!
Can there be a separate option for custom properties other than inherit from parent? Something so that if a custom property isn't defined on a connection itself, it will attempt to use it from the parent, and if it isn't there, it'll attempt to use it from the parent of that object all the way up the hierarchy?
Alternatively, allowing individual inheritance per custom property would be nice, but I understand how that could become confusing. Maybe when selecting inherit if a property exists from a parent that once will be locked but allow us to add non-inherited properties?