What design pattern I should use if I want to work on something that could be generalized later

Imagine that I am working for a software company A, and the company has a dedicated business unit B working on a set of infrastructure technologies. And I work in the business unit C, and we use the system been built by B to develop our own system. Currently, if the systems built be Business unit B is insufficient to support our use case, and we want business unit B to improve their system to support us. However, our request is not highest pri for B at this moment, and we have to build our in house solution.

Now the question is, when building our in house solution, if we want to generalized this system to business unit B in the future, what should we keep in mind when building our system.

The answer I am looking for are like: should be build a library so that others could link to, or should be build our system to be a service that others could call, or should we work with business unit B together at design stage to develop some parent class for the basic unit, and our system inherit from. Or, any suggested design patterns we should use ? etc