my $g = Mail::Message::Field::AddrGroup->new(name => 'name'); my $a = Mail::Message::Field::Address->new(...); $g->addAddress($a);
my $f = Mail::Message::Field::Addresses->new; $f->addGroup($g);
See SYNOPSIS in User::Identity::Collection
An address group collects a set of e-mail addresses (in this case they are Mail::Message::Field::Address objects).