Even if there would be such way to do it reliably then you would hit the wall with not being able to call getsockopt on that as SO_ORIGINAL_DST is not supported by Erlang. You can try to write your own ranch_transport which would use socket module instead, but that will be tremendous task which would require quite a lot low-level understanding of BEAM. Question is whether it is feasible.

EDIT: maybe there are better solutions for what you need. You can use for example L7 proxy instead of L4, and that can add proper header to HTTP requests, or you can use socket activation to make application listen on restricted port instead of L4 proxying.