One way to share a workbench between products would be to simple add a reference to the workbench for each test case which use the relevant workbench, this makes the test case completely independent of the product and means that it can be executed without worrying about also opening the correct workbenches.
In the example above both the Alpha and Beta product uses Test Case 2, but only the Alpha product use Test Case 1. Both test cases use the Serial Port workbench.
An easier way to do it is to let it be up to the projects to reference the correct workbenches for that particular product.
