I think nobody is replying because we dont fully understand what you are trying to do.
Maybe it is SRc nat that you want to use... You should be able to Nat across any address or range of adresses inside the network to another address that is outside the network.
I use that a lot to Nat across a customer phone IP address from inside the network (his!) (lan side) to another address on the Wan side of my cpe.
I want to do this:
Every request that will come to my public IP (from outside) I want to redirect to another IP on internet.
I dont want to to redirections to my local IPs. It is external redirect.
For example: You (you are not on my network) want to connect to 184.108.40.206 (my public IP) and it will redirect you to 220.127.116.11 (this ip is not on my network)