postfix remote received header

I have two servers SERVER -1 (S1) and SERVER -2 (S2)(Based on centos 5 + Postfix). S1 contains my software and S2 is a SMTP. S1 submits mails to S2 and S2 mails to REMOTE STMP.

Received mail show the information of Both servers in "Received" header. I want to show the information of only S2, not of S1.

My Header as follow

Delivered-To: [email protected]
Received: by 10.146.167.20 with SMTP id p20cs104988yae;
        Tue, 25 Oct 2011 22:47:14 -0700 (PDT)
Received: by 10.52.34.177 with SMTP id a17mr14374982vdj.103.1319608033913;
        Tue, 25 Oct 2011 22:47:13 -0700 (PDT)
Return-Path: <[email protected]>
Received: from ns5.labs.com (ns5.labs.com. [184.107.181.34])
        by mx.google.com with ESMTP id h8si507643vdv.12.2011.10.25.22.47.13;
        Tue, 25 Oct 2011 22:47:13 -0700 (PDT)
Received-SPF: neutral (google.com: 184.107.181.34 is neither permitted nor denied by best guess record for domain of [email protected]) client-ip=184.107.181.34;
Authentication-Results: mx.google.com; spf=neutral (google.com: 184.107.181.34 is neither permitted nor denied by best guess record for domain of [email protected]) [email protected]
**Received: from ocpm.co.in (50.23.42.114-static.reverse.softlayer.com [50.23.42.114])
    by ns5.labs.com (Postfix) with ESMTP id 2A3196B28261
    for <[email protected]>; Wed, 26 Oct 2011 01:47:10 -0400 (EDT)**

Here my smtp server 2 (ns5.labs.com) and i am submiting mail from ocpm.co.in. how to i remove detials of ocpm.co.in


To be more precise: You are not supposed to alter these headers. This is the excerpt of RFC 5321 Section 3.7.2:

When forwarding a message into or out of the Internet environment, a
gateway MUST prepend a Received: line, but it MUST NOT alter in any
way a Received: line that is already in the header section.