Sub contracting and lot charges

Looking for advice on creating a P.O line for 1 lot charge for a sub
contracting requirement i.e. black anodizing, that consist of several
different jobs for different parts. We use the part number we are building
for the sub contracting part number. Currently we create separate lines for
each job on the P.O. The invoice comes from the vendor for one lot charge
and then A/P has to allocate the lot charge manually to each Job. We are
still on 3.0.632. Any help would be appreciated.

Thanks
Dan Shallbetter
States Electric Mfg.