How to merge docker with rpc?

Question

Node.js

Hello.
I have a number of services. One service - one container. Of these, all one client, all other servers, the client is HTTP. The crux of the matter is how do I put it all together? After all, you need to separately specify the internal port for the container from which I send the request, and I still did not find the right answer in the gRPC documentation.
What I use:
Client - NestJS
Servers - pure nodejs
RPC - gRPC

ps If someone can provide a link or explain how rpc works in general, I would be grateful. Thanks