If the line separating the pages is always the same, you could set $/, aka $INPUT_RECORD_SEPARATOR (see perlvar) and read a page at a time pretty easily.

$/ = "----- PAGE SEPARATAAAR -----\n";
while (<>) {
    chomp;
    # $_ now contains the HTML page
}
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If the separator is something you'd have to match with a regex, you could read a line at a time and detect page boundaries.

my $page = '';
while (<>) {
    if ( /xxx PAGE BOUNDARY \d+ xxx/ ) {
        output( $page );
        $page = '';
        next;
    }
    $page .= $_;
}
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