"Make to Hold"

We are a custom manufacturer that provides our customers what we refer to is "Make and Hold" inventory.  Because some of our clients don't have the ability to stock the inventory we produce we offer a service that we will stock and keep track of their inventory as a value added service.  The issue we run into is the inability to maintain/capture this inventory as a function in MAS90/100.  Is there a module that will assist in this process?