Forward an IP address to a different IP address

I want all outgoing traffic going to a specific IP address to actually go to a different IP address, BUT only for a certain network group.

I have servers in a network group, and if they attempt to access 1.1.1.1 I want to to actually goto 2.2.2.2. But I need this only for my server network group.

I have tried various config for NAT, but nothing seems to work.