Hi mrinal,
CASO is only 1 part of this, and would be used for central management. The component you are really interested in for your particular scenario is SAN Shared Storage Option (SAN SSO) which has been missed in the post above mine.
CASO won't give you the ability to backup another media server directly to an FC-attached tape drive at all. SAN SSO, licensed through ESO, will. CASO would delegate jobs etc, but not share a tape library. SAN SSO accomplishes this, and allows a number of media servers to access the tape library as if each had exclusive access to the library. The Primary SAN SSO server will control this, with each remote server having a full installation of BE on it with associated application licenses and LEO licenses.
Read the technical brief below to get a better understanding of it, and check out the link on what SAN SSO is:
http://www.symantec.com/business/support/index?page=content&id=TECH196579
http://www.symantec.com/business/support/index?page=content&id-=HOWTO24287
Thanks!