inheriting a custom property from a supergroup ("effective" custom property)

[Dr. Hawkins]

I have an id number, call it unDna, for entries in my database.  When
elements are displayed or manipulated, either the card or the group I've
placed has unDna set as a custom property.

The handlers for close field check for a unDna of the field or the owner of
a field.

This backfires, though, if the field is in a subgroup, or a subsubgroup,
etc.

I'm trying to think of a clean way to handle this; to this point, I've used
"the unDna of the owner of me"

I could recursively climb ownership, looking for a unDna that has been
set--but not being set indicates that it's a different type of data.

Or I could, on creation, cycle through groups and set unDna for all the
fields, or all the groups, but that sounds ugly and prone to error.

I suppose that what I'm really looking for is "the effective unDna of me",
but there does't seem a language provision to implement that.

ideas?

-- 
Dr. Richard E. Hawkins, Esq.
(702) 508-8462