Using SQUID or other proxy for non-http traffic (Modbus/TCP)

I'm trying to figure out how to provide a proxy server for Modbus/TCP traffic. This is non-http traffic (industrial protocol), and usually connects to port 502.

The purpose is to give remote devices a static IP address which they can connect to (i.e. a cheap cloud server) while supporting dynamic IP addresses at the destination (i.e. standard DSL/cable internet).

Can SQUID (or other linux-based proxy) be configured to

1. Listen on port 502 for incoming connections

2. Transparently pass the connection on to an IP address which is specified in the configuration file

3. Support dynamic destination IP addresses, possibly linked to a dynamic DNS update client or hostname?

Suggestions for accomplishing this are greatly appreciated.