my %original_hash = ( first  => 'alpha',
		      second => 'beta',
		      prime  => 'alpha', );

foreach $key (keys %original_hash)
{
    push @{$reverse_hash{$original_hash{$key}}}, $key;
}

foreach $rkey (keys %reverse_hash)
{
    print "$rkey = ".(join ', ', @{$reverse_hash{$rkey}})."\n";
}

print "\n";
my %test_hash = reverse %original_hash;

foreach $tkey (keys %test_hash)
{
    print "$tkey = $test_hash{$tkey}\n";
}