Inventory

Can we allocate inventoried stock to Jobs and have this reflect on stock levels without creating an invoice?  We are an electrical company that generally buys materials that go directly to the job site and can be allocated to the job directly.  But occassionally we bulk buy certain stock items which we inventory and track.   But as stock gets taken for various jobs we need to allocate these items (to track job costs) without invoicing the client as this is already costed out. Any solutions?