Okay how about this?

#!/usr/bin/perl -w

use strict;

my @foo;
$/="";

$_ = <DATA>;
while (s/(\d+ is good.*?)<HR>//s) {
    push @foo, $1;
}
print $_, "\n--------------\n" foreach (@foo);

__DATA__

<HR>
1 is good<BR>
useless data<BR>
useless data<BR>
useless data<BR>
useless data<BR>
<HR>
2 is not good <BR>
useless data<BR>
useless data<BR>
useless data<BR>
useless data<BR>
<HR>
3 is good<BR>
useless data<BR>
useless data<BR>
useless data<BR>
useless data<BR>
<HR>
4 is not good <BR>
useless data<BR>
useless data<BR>
useless data<BR>
useless data<BR>
<HR>
[download]