how to build dependant packages across multiple machines

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I have a package running a service (package A) and another running a client for that service (package B) both implemented in c++. Package B has build/exec dependency on package A for that service. Both compile and work fine when they are in the same workspace of a single machine.

Now if I want to run a distributed system and move package A on machine A and package B on machine B , what would be the best way to handle this build dependency?

or in other words, how can i build package B on machine B without having package A on that machine?

I am sorry if there is an obvious answer but I am having trouble researching this information.