while( $file =~ /\Q$start\E(.*?)\Q$end\E/sg )
{
    $a = $1;
    $match = $&;
    
    #look for more start tags in what we matched 
    while( $a =~ /\Q$start\E/sg )
    {
        #balance the ending comments
	$file =~ /.*?\Q$end\E/sg;    
        $match .= $&;
    }
    print $match, "\n";
}