Maybe an END block:

END {
    kill 'INT' => keys %children;
}
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If you keep the PIDs for your kids in %children, that'll do it. For example, the following script dies, but still prints the ending notice:

#!/usr/bin/perl -w

use strict;

BEGIN {
    print "This is at the start\n";
}

die;

print "This is in the middle.\n";

exit;

print "This should never print.\n";

END {
    print "This is in the end.\n";
}
[download]