Chad,
thank you for the feedback.
You could import group memberships just like any other attribute, but need to be aware that eDirectory stores a membership in 4 separate attributes:
'Group Membership' and 'Security Equals' on the user, 'Member' and 'Equivalent To Me' on the group.
Hence the import is a just little more complex.
But you can create your CSV accordingly, or run the same CSV multiple times with slight changes.
See also the "Assistant" "Manager" example in ch.5.2 of the documentation.
Good luck
Wolfgang