Hi Surjit,
You can run only one PRD system under one sap license.
Please check below link for more information
http://intelligentlicensing.com/wp-content/uploads/2012/08/IL_SevenSteps_Whitepaper_electronic-2.pdf
http://www.xpandion.com/SAP-Licensing/sap-licensing-quick-guide.html
BR
Aj