open :F html input.html ;
for my $h2 in //h2 {
    my $h1 = $h2/following-sibling::h1[1] ;
    my $chunk ;
    if $h1 {
        $chunk = $h2/following-sibling::text()[following-sibling::h1[1]=$h1][preceding-sibling::h2[1]=$h2]
               | $h2/following-sibling::*[not(self::h2)][following-sibling::h1[1]=$h1][preceding-sibling::h2[1]=$h2] ;
    } else {
        $chunk = $h2/following-sibling::text()[preceding-sibling::h2[1]=$h2]
               | $h2/following-sibling::*[not(self::h2)][preceding-sibling::h2[1]=$h2] ;
    }
    if $chunk {
        my $div := insert element div after $h2 ;
        xmove $chunk into $div ;
    }
}
my $divs := wrap div //h2 ;
save :F html :f output.html ;