Each service has its own code directory, and there's one big "shared code" directory. When you build one service, you copy the shared code directory and the service-specific directory, move to the service-specific folder, run your build process. The artifact that results is that one service. Tagging becomes "<service>-<semver>" instead of just "<semver>". You may start out with deploying all the services every time (actually hugely simplifies building, testing, and deploying), but then later you break out the infra into separate services the same way as the builds.