In the CCL I have many custom parametric products using sub assemblies I found this rather easy to accomplish.

One product is a custom base which can have multiple bays usually no more than 6. I used a base cabinet with division as the core then modified and added prompts so that now the user enters the width (height & depth are constant) selects the number of bays, runs the bay width calculator as there are some that are a constant opening width, then selects the opening options from the bay drop down.  These opening selections are a list of sub assemblies that I created. Made perfect sense as they could be used in any bay location and were parametric so they auto size and the opening width changes.

I have numerous products like this but when looking into the Foundation library I don't see what I need to replicate these products, or I am looking in the wrong place.  I do think that i could accomplish the task but it would be more difficult and take longer.  What am I missing.  Lenny please chime in here.