Hi Sudhakaran,
Since your DEV+QA of Network A should have connection with PRD of Network B anyway (RFC-connection, etc), there is a better way of doing the transports, and the data+cofiles will be automatically transferred to PRD.
This is using the "domain-links".
So basically you will create 2 transport domains, one for DEV+QAS and one for PRD.
Please check this doc and click the domain-links to see how to setup one: http://help.sap.com/saphelp_erp60_sp/helpdata/EN/c4/6045377b52253de10000009b38f889/content.htm
I hope this will help you.
Regards,
Andre