In this case you should really do one query and use the "group" tag to avoid unnecessary queries, somehow like this:
db_multirow people people {
select p.last_name, e.email from
persons p join email_addresses e on p.person_id=e.person_id
order by p.last_name
}
and in the adp:
<multiple id="people">
Name: @people.last_name@
Emails: <group column="last_name">@people.email@</group>
<p>
</multiple>
(this example is untested and propably buggy, but you get the idea)
