Setup a caching server (Apache Traffic Server or Squid or similar)

We need to setup a caching server using Apache Traffic Server or Squid proxy. Apache Traffic Server seems like the way to go - but I am open to suggestion. Currently, when we browse the web, we do the following: Web Client (Browser, curl etc) => Remote Proxy Server (Hop1) => Remote website What we want to achieve is the following: Web Client (Browser, curl etc) => Our internal caching server (Hop1) => Remote Proxy Server (Hop2) => Remote website The main challenge: Web Client (Browser, curl etc) should be able to set any Adhoc Remote Proxy Server IP address at any time, and it needs to go via internal caching server (Hop1) and then use the above set remote proxy server IP in Hop2. So most importantly, every HTTP request sent could change the remote proxy server IP, while still going thru the Caching proxy server. Bottomline: We want to use Remote proxy server each time, and still cache the content in the middle internal caching server. Deliverable: A fully working docker image with the config files, settings etc - along with its docker-compose file.