How to use the same javascript custom package in two different folders without repeating it?

I’m building a microservice and dockerizing it. My folder structure looks as following:

Root
|
|--DockerPacks
   |--ProjectA
      |-docker-compose.yml (builds ServiceA & ServiceB)
|--Microservices
   |--ServiceA
      |-lib
        |-PackageA
      |-src
      |-index.js
      |-Dockerfile
      |-package.json
   |--ServiceB
      |-lib
        |-PackageA
      |-src
      |-index.js
      |-Dockerfile
      |-package.json

So in both services (ServiceA & ServiceB) I need to use the same custom package (PackageA inside lib folder) and I don’t want to have it twice. How could I do this? All help is appreciated.