use Net::OpenSSH::Parallel;
my $pssh = Net::OpenSSH::Parallel->new;

for my $server (@targets) {
  $pssh->add_host($server);
}

$pssh->push('*', command => @stuff);
$pssh->push('*', command => @more_stuff);
$pssh->run;

# ...

$pssh->push('*', command => @even_more_stuff);
$pssh->run;