Hi Ranga,
For such requirements, I would recommend to use ACE ( Access Control Engine ).
ACE is meant to authorize users on data level.
Refer below links :
http://help.sap.com/saphelp_crm700_ehp01/helpdata/en/b8/bfe252051048e2bcbdc9129ab5f95b/frameset.htm
Regards,
Naresh