Cisco ISE Deployment suggestion required

Question

Require Assistance on Cisco ISE Deployment for below scenario
-- We have Three Cisco ISE Appliances and Client has taken Advance Subscription License for 500 users
-- Client has DC & DR and needs to deploy the Cisco ISE in one Main Office which connects to DC & DR on MPLS Links
-- Client suggestion was to deploy one ISE node ( Admin + M&T + Policy Server ) in DC and its Standby Secondary in DR
     and only deploy Policy Server in Main Office.
     Idea behind the design is that ,
     1) If DC fails , Cisco ISE related logs will get generated on DR and any Cisco ISE related request will be taken care by Local Policy Server in Main Office .
      2) If Local Policy Server Fails , then ISE node in DC will act as Secondary backup and DR will act Teritary Backup
      below is view
                                     DC
                        Primary Node with Role
                   [Admin , M&T , Policy Server]
                                                                                                             Main Remote Offic
                                                                                                              Cisco ISE Node ( Only Policy Server) -----------> Network Devices
                               DR
                       Secondary   Node with Role
                   [Admin , M&T , Policy Server]
Please let me know is it possible

Answer 1

Yes, The scenario is quite achievable also please  review the below link for assistance on deployment of ISE.
http://www.cisco.com/en/US/solutions/collateral/ns340/ns414/ns742/ns744/docs/howto_50_ise_deployment_tg.pdf
http://www.cisco.com/en/US/docs/security/ise/1.0/install_guide/ise10_deploy.pdf