The easiest way is to convert

FLINTSTONES -- BARNEY, FRED, WILMA
JETSONS -- MAX, TONY, WILMA
SIMPSONS -- LISA, BARNEY, WILMA, HOMER
ALCATRAZ -- ELIJAH, MAX, WILMA
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to

my %is_in_show = (
   MAX    => [ 'JETSONS', 'ALCATRAZ' ],
   WILMA  => [ 'FLINTSTONES', 'JETSONS', 'SIMPSONS', 'ALCATRAZ' ],
   HOMER  => [ 'SIMPSONS' ],
   ELIJAH => [ 'ALCATRAZ' ],
   ...
);
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when you read the file. The following accomplishes this:

while (<FILE>) {
   chomp;
   my ($show, $names) = split(/ -- /);
   my @names = split(/, /, $names);
   foreach my $name (@names) {
      push(@{$is_in_show{$name}}, $show);
   }
}
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