I use an ugly but working procmail configuration for something like this. It adds an address to the List-Id header of the email, or creates that header if it doesn't exist. You could do the same with Subject. Here are the relevant lines from the procmailrc on that host.

The first rule says to save a copy of the mail to a local mailbox. The second changes the headers. The third rule asks procmail to do the forwarding. The two email addresses are changed to an example here. 

:0 c
inmails

:0 fhw
| perl -pe '$d = "Some Label <some.label\@example.com>"; $t or do { s/
+(^List
-Id\s*:\s*)/$1$d, /i || s/^$/List-Id: $d\n/ and $t++; }'

:0
!forward.target@example.net

[download]

In reply to Re: Redirect email by ambrus
in thread Redirect email by Gangabass

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.