Cisco VPN :: 5550 Assign Static IP To VPN Clients In Redundant VPN Infrastructure

We have a Highly available VPN infrastructure across two data centers. We also use ACS 4.2 servers for authentication. The ACS servers are in teh same "cluster" in a Primary and Secondary fashion.  Site A has primary ACS and primary ASA 5550 IPSec VPN termination. Site B has secondary ACS and redundant ASA 5550 IPsec VPN termination. We also use InfoBlox for DHCP IP address assignments. The two IPSec VPN Head end devices, ASA 5550s, they use different subnets for IP pools for the VPN Clients. Site A uses x.x.24.0 and Site B uses x.y.24.0. As indicated VPN clients authenticate using teh ACS 4.2 Radiius server. I can assign static IPs per user on the ACS server but this can only work for the primary site. Once static IP address is assigned on primary ACS for a user, this status will be replicated to the secondary ACS on Site B. When the Primary IPSec VPN Head End ASA or Internet fails on Site A, Clients on DHCP will work fine seemlessly via Site B. But for the static IP users, you have to change the Assigned Static IPs to match the subnet on Site B. How I can assign static IPs to clients via both Sites without manual intervention. Either via DHCP or ASA. I was trying to stay away from creating multiple Groups for VPN and also avoidng creating local ASA users because these options will not scale well as static user base increases. I need users to get a static IP address from Site A subnet when connected to Site A and get a static from Site B subnet when connected through Site B.