how to link a job number to the relevant engineer

I have a spreadsheet that that logs jobs through our shop and each job number will be linked to an engineer. however an engineer can have more than one job number assigned to him. In a separate sheet I log shipping details for the parts made and if they are ready to collect etc. In this sheet i want to be able to enter the job number to be shipped, and the engineer name column automatically fills the correct name in.

I'm finding it hard as it is not just a name to a number.

example of datasheet

       a          b         c
job number      part      engineer
   9001        tag          tim
   9002        bolt         ben
   9003        nut          tim

shipping sheet

      a           b             c
job number      status      engineer
   9002        sent          ben
   9001        ready         tim
   9003        ready         tim

so when i enter the job number in shipping sheet column A, it auto fills Col C by using the data from the datasheet.

hope that makes sense, i have tried;

=if('shippingsheet!'a1:a100= 'datasheet!'a1:a100,'shippingsheet!'c1:c100='datasheet!'c1:c100)

i know its way off but dont have any idea how to link them because its all random.