How to create one common harness?

Hi

I have big Simulink model with contains of subsystems. Each subsystem is a link to the custom Simulink library. But they are not unique. I mean, that there could be two subsystems with links to the one common custom Simulink library.

I'm creating Simulink Test Harnesses for each of these subsystems. But as i said, they could be same.

So, is it possible to have one common Simulink Test Harness model for this different subsystems which are links to the same library?