How to mirror requesets to docker containers

I'm looking for a way to mirror requests sent to specific domain (which is proxied by Traefik) to every Docker container (of that specific service) at specific port.

Context: Traefik is deployed as Docker Service and updates config from Docker Swarm.

More specifically, I want to setup a bunch of Tor instances (incoming HTTP proxy requests are handled by Privoxy so Tor receives them in socks5) which are controlled simultaneously. So the basic part of configuring this just as proxy was easy - done. And I could do the same for another port (and new domain), but I need to mirror all incoming requests to ALL containers. And these requests are going to controller port of Tor process - they work as signals.