How would i go about running baikal in docker, but with nginx external on the system?

Ive got a server, and i have nginx running on the system (that is, not in a container) and a bunch of containers running in docker proxied by it. I want to add baikal, but all the information i can find assumes its going to be the only service running and includes nginx within the container. Baikal documentation itself doesnt talk about docker, and the community docker image doesnt go into detail in its documentation.

I of course want tls, proxy_pass doesnt appear to work for cgi and fastcgi_pass is used by baikal for the internal fastcgi server. I have to use this, as every docker container has a web server and i have to have localhost open other ports (12380:80 and 12343:443 in the case of the baikal container). How would i go about configuring nginx in this case? Im at a loss and its probably something very simple but i cant seem to figure it out.