How to configure proxy for one backend service

Heya,

I have traefik running as a service on a private network with an internal IP address.
I want to use it to be a front end to some static files we have in S3
Normally this wouldn't be an issue - point back end at the S3 url and you're done.

However, I need to pass the traffic from traefik, via a proxy, to reach s3. The traefik machine doesn't have access to the internet itself (and we haven't got direct connect setup yet for the aws side...)

Any ideas how I can do this?

Basic flow is

Laptop -> traefik "docs.whatever.com" -> proxy -> ~internet~ -> s3

Usually I use consul k/v store to create the backends, so I put that down and file as I don't mind going from one thing to the other - its just how to say for this backend, use a proxy, no others.

Thanks!

Hmm no clues? I suspect it will not be possible as I can't find anything in the documentation which is a shame! Ah well, back to square one