How to organize an IP Proxy server?

Question

Computer networks

Good afternoon.
Who can tell if it is possible through a proxy server to organize the distribution of IP traffic between two hosts and the subsequent return of this traffic? The algorithm should be approximately the following for one direction
1) We select the necessary networks on the router and redirect them to the Proxy
2) The proxy selects packets from this traffic that need to be sent to server A and server B, forwards
3) Server A and server B processes this traffic and returns towards the proxy
4) The proxy sends the traffic returned from A and B towards the router
5) The router sends traffic towards the Internet (for UL) or towards the client (for DL)

Answer 1

iptables, or another firewall capable of NAT + routing table.

Answer 2

You can, it's called routing tables and NAT + the fact that you have a "proxy" falls out of the hema :)