I have a similar problem.
In our context we manufacture in 2 steps, a batch of finished goods that is QC-ed and assigned a lot #. That 'batch' may be consumed by multiple finished goods in the form of different package types. Each package type has its own item number. There are many different reasons for this, most are customer driven.
It would be helpful to output 2 or more finished goods in a single production order that consumes the afore mentioned batch.