.
.
.
open my $schdIn, '<', \$scheduleData or die "Can't open 'Schedule': $!";
my %actorSchedules;
my $scheduleName;

while (defined(my $line = <$schdIn>)) {
    if ($line =~ /SCHEDULE\s+(\S+)/) {
        $scheduleName = $1;
        next;
    }

    next if $line !~ /(\S+)#(\S+)/;
    ++$actorSchedules{$1}{$scheduleName};
}

open my $agentsIn, '<', \$agentData or die "Can't open 'Agents': $!";

my $agentsList  = join '|', map {chomp; qr/\Q$_\E/} <$agentsIn>;
my $agentsMatch = qr|\b($agentsList)\b|;
my $wantedSchedule = 'Wanted';

open my $defsIn, '<', \$defsData or die "Can't open 'Definitions': $!";

while (defined(my $defLine = <$defsIn>)) {
    chomp $defLine;

    next if $defLine !~ /$agentsMatch#/;

    my $lineout = $defLine;
    my $tail   = $actorSchedules{$1}           ? 'Yes'    : 'No';
    my @schedules  = keys %{$actorSchedules{$1}};

    $tail = join ' | ', $tail, @schedules;
    print "$defLine | $tail\n";
}

##</code><code>##

Mindy#mu4 | Yes | Wanted
Orlon#mu5 | No
Nancy#mu6 | Yes | Unwanted
Harry#mu7 | No