for my $key (keys %AoH) {
    for my $domain qw(ns7.xxx.com wrnadc02.xx.xxxxxx.com) {
        nsqry($domain, $_ ) for @{$AoH{$key}} ;
    }
}

##</code><code>##


my @domain = ( {NAME => 'ns7.xxx.com',              IPLIST => []} # IPLIST gets populated dynamically, as discovered
             , {NAME => 'wrnadc02.xx.xxxxxx.com',   IPLIST => []}
             );
my %IPinfo; # This will be a HoH

for (qw (10.220.84.30 10.220.84.51 10.220.84.52 10.220.84.54 ...){
   $IPinfo{$_}= {DOMAININDEX => undef,  TYPE => "CLIENT"};
}

....
OUTER: for my $ip (keys %IPinfo){
         for my $domidx (0..$#domain){
           my $ptr = nsquery($domain[$domidx]->{NAME}, $ip) ; # Assuming "nsquery" has been modified to return the info
           next unless $ptr; # No change, if $ptr is empty
           $IPinfo{$ip}{DOMAININDEX} = $domidx; # Forward ref from IP to DOMAIN
           $IPinfo{$ip}{PTR} = $ptr;
           push @{$domain[$domidx]->{IPLIST}}, $ip; # Keep a list of IP's that live in this domain
           next OUTER; # we bail after the first domain found (More efficient)
         }
}