Thanks for the help/reply. I've been trying to modify your code b/c is currently does not remove the lines for each section prior to line ^DATA So, at the moment the sample data looks like this 
EHLO testdomain.com
MAIL FROM:<outsideuser01@outdomain.com> SIZE=1016 BODY=7BIT
RCPT TO:<testuser01@testdomain.com>
RCPT TO:<testuser02@testdomain.com>
DATA
Received: from 1.1.1.1(helo=mvastnlufgt.mgrjofpxydauvu.info)
        by  with esmtpa (Exim 4.69)
        (envelope-from )
        id 1MM6HB-1114fm-3T
        for testuser01@testdomain.com; Sun, 9 Jan 2011 23:07:59 +0100
From: "outsideuser01" <outsideuser01@outdomain.com>
To: <testuser01@testdomain.com>
Subject: Re:   good evening
Date: Sun, 9 Jan 2011 23:07:59 +0100
MIME-Version: 1.0
To: <testuser01@testdomain.com>
To: <testuser02@testdomain.com>

[download]
It's correctly appending the RCPT lines but not removing the DATA before the line that starts with ^DATA Should look like this, note how it remove all line prior to ^DATA but only for the corresponding section. 
Received: from 1.1.1.1(helo=mvastnlufgt.mgrjofpxydauvu.info)
        by  with esmtpa (Exim 4.69)
        (envelope-from )
        id 1MM6HB-1114fm-3T
        for testuser01@testdomain.com; Sun, 9 Jan 2011 23:07:59 +0100
From: "outsideuser01" <outsideuser01@outdomain.com>
To: <testuser01@testdomain.com>
Subject: Re:   good evening
Date: Sun, 9 Jan 2011 23:07:59 +0100
MIME-Version: 1.0
To: <testuser01@testdomain.com>
To: <testuser02@testdomain.com>

[download]

In reply to Re^2: Help appending data based on location by Anonymous Monk
in thread Help appending data based on location by perlnewbie9292

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