how to configure Squid with ONE Network Card for cache and proxy

hello all,
how i can configure Squid with ONE Network Card for cache and proxy as shown in image attached.

I am not sure if it would work, but you could always do the following:

Make it a VM and assign it multiple virtual NICs

Set up multiple VLANs on the port it is connected to and create a virtual Ethernet device
Secure Systems Administration: Creating Virtual IP Addresses on Linux