You could use a Hash of Hashes, so that instead of having one key, you'd have two.

Some of your code from above would change from:

$NetNameAndFanout = join (" ",$NetName,$NetFanout);
$NetStatsHash{$NetNameAndFanout} = join (" ",$NetCap,$NetRes,$NetLengt
+h,$FirstDriver);
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would become

$NetStatsHash{$NetName}{$NetFanout}{Cap}    = $NetCap;
$NetStatsHash{$NetName}{$NetFanout}{Length} = $NetLength;
$NetStatsHash{$NetName}{$NetFanout}{Driver} = $FirstDriver;
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In that way, instead of

    foreach $KeyNetName (keys %NetStatsHash) {
        @KeyEntries = split (/\s+/,$MasterKey);
        $KeyNetName = $KeyEntries[0];
        $KeyFanout = $KeyEntries[1];
        $OkayToAdd = 0;
        if ($KeyFanout == $i) {
            @NetDetails = split (/\s+/,$NetStatsHash{$MasterKey});
            $NetCap = $NetDetails[0];
            $NetRes = $NetDetails[1];
### etc.
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you'd say

    foreach $KeyNetName (keys %NetStatsHash) {
      foreach $KeyFanOut ( keys %{ $NetStatsHash{$KeyNetName} } ) {
        $OkayToAdd = 0;
        if ($KeyFanout == $i) {
            $NetCap = $NetStatsHash{$KeyNetName}{$KeyFanOut}{Cap};
            $NetRes = $NetStatsHash{$KeyNetName}{$KeyFanOut}{Length};
### etc.
      }
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This is untested, but the principle is there... Good luck, and post if there are any problems or further questions.