SQUID port to port

Hi,

Here comes another squid question:

It is possible to have a squid proxy working like this:

listening on port 80 and forward connection to ip1 on port 8080
listening on port 81 and forward connection to ip2 on port 8181

Both options at the same time.

I have seen that you can set several listening ports.

http_port 80 81

but I don't know if squid can listen at the same time.

Thanks a lot!

Sergio