Lookup fields display does not make sense

Lookup fields display does not make sense

in my form I have several Lookup drop downs. Each one contains a code # for a part option and the purpose is to build a complete part number made up of all the individual options chosen. Each option table has 2 fields, Part# and Description, for example One of the Tables may have Part # Q36t , Q39t, G34d etc are in a part numbers Fields and Heater Option36W, Black Paint Option, and Steel Option.
 I appreciate the feature of being able to associate the 2 fields in the Display Fields so that when I click the Part# drop down, it displays the Description also for each option, (without which the user would have no idea what the code means), for example Q36t - Heater Option 36W.
However, when I click Submit, the entire part# AND description is posted to the table. This does not make sense. Why would I have made them separate fields if I wanted them posted as 1 field item. 
I only want the Code number posted.
2 Questions.
1) Is there a way to only post the Code# but still make the description visible when choosing from the drop down.?
2) If the above is not possible, is there a way to strip away the description from this field when I output to a report or a web page? As I said, the purpose is to post a complex part number made up of all the individual option codes chosen.

Any help would be appreciated.