Cisco Firewall :: 2911 - NAT Any Source Address From Internet

I'm using a 2911 as our Public Internet Edge Router. I have 2 public sub net blocks from Sprint, we are in the process of migrating. What i need to do is NAT any source address from the Internet from an address on one of our public blocks to the other.
 
Example:
 
Source Address 11.10.10.10 ==> Destination 64.165.123.10 (nat this to 64.165.54.10) inbound.
 
So if from the internet tries to hit 64.165.123.10 we want to nat that to 64.165.54.10 both of which sit on our public space.