use Win32;
my( $domain, $sid, $type );
foreach my $id (  "Administrator", "Administrators",
        "Domain Admins"  ) {
    if(  ! Win32::LookupAccountName(
            "", $id, $domain, $sid, $type )  ) {
        warn "Can't lookup SID ($id): $^E\n";
    } else {
        print "$id is of type $type and belongs to $domain.\n";
    }
}
__END__
Administrator is of type 1 and belongs to MY-COMPUTER.
Administrators is of type 4 and belongs to BUILTIN.
Domain Admins is of type 2 and belongs to MYDOMAIN.