How To Get The "groups" Reliably Without Dupes?

[Bryant Fong]

I want to get all the contacts, and the unique group associated with that
contact. Unfortunately, one person might show up under both "Buddies" and
"Other". If the user explicitly moved the person to a group (e.g. Buddies),
I want that one to be used.

I thought I would be able to enumerate the list of contacts and then use:

contact.get_Property(MCONTACTPROPERTY.MCONTACTPROP _GROUPS_PROPERTY);

But this just returns nothing. Instead, I can enumerate the groups and get
the contacts, but then I will get dupes. Moreover, I don't know which group
is the "real" one. Especially when Messenger is is non-English languages.

What's the solution here?