You're looking for Network Address Translation, although a typical google search on the term won't help you much because you're looking to do the reverse of what most NAT devices (home routers) do - you want to rewrite the destination IP of outbound traffic, rather than the source IP.
You'll likely have a hard time doing this with a home router or all-in-one wireless gateway, but almost every professional-grade router will do the trick. Using linux and iptables, you should be able to accomplish this on a firewall with something like:
iptables -t nat -A PREROUTING --dst 158.204.281.222 -p tcp --dport 80 -j DNAT \
--to-destination 160.201.21.239