my %users = {"1" =>"none", "2" => "admin"...};
my %pwds = {"1" =>"admin", "2" => "foobar"...};

##</code><code>##

...
my $curpwd = "admin";
if (defined $pwds{$i}) {
  $curpwd = $pwds{$i};
}
if ($users{$i} eq "none") {
  $session->login(Password => $curpwd);
} else {
  $session->login(Name => 'admin', Password => $curpwd);
}