In addition to the concerns you have already raised, there is another -
taking a mailing list compiled by one organization and using it to do a
mailing for another organization - regardless of the relationship between
the organizations - is, essentially, the sending unsolicited bulk email,
aka spam. Individuals whose addresses appear on the list *MAY* have agreed
to receive email from the international organization. That does not mean
they agreed to receive email from anyone and everyone associated with the
international organization. A mailing of this nature may violate your
site's acceptable use policy.

You may want to consider asking the international organization to do the
mailing for you. After all, it is their list and the individuals on it
have apparently agreed to receive email from them. If the international
organization declines to handle the mailing, ask them to explain.

If a Notre Dame faculty member came to me with a request of this nature,
I would give that faculty member the same answer.

--
Paul Russell
Senior Systems Administrator
University of Notre Dame