Closing this as the original person seems to have moved on and not
gotten docs/writeup on the wiki or in the docs.

Also for people implementing this in the future, I would suggest a
mailing list or alias at the MTA level and have the "group users"
email address send to the mailing list.

Alternatively, some mechanism to assign all people in a group to the
nosy list would work. As this allows individuals to unsubscribe from
particular issues.

Also if any sort of ACL is set up based on who is on the nosy list,
having the individual members of the group on the nosy list will
work as expected.