s{(<name>.*?</name>)<value>(.*?)</value>}{
    $1 . join '', map "<value>$_</value>", split /\|/, $2
}seg;

##</code><code>##

s{<name>.*?</name>\K<value>(.*?)</value>}{
    join '', map "<value>$_</value>", split /\|/, $1
}seg;