Find records and New Record scripts

I have a form with some fields for entering data into an inventory table. There is a portal on the form that shows the records related through a self-join to the PartsCode field in the Inventory table. I need to have the PartsCode field on the form perform two functions. One for entering new records and one for finding the related records in the portal.The PartsCode field has a popup with the list of Partcodes from a related bill of materials. Currently, when I select an item from this popup, it will find related the records in the portal, just through the relationship, but it also automatically creates a new record in the inventory table. This I can't have. I want it to add new records only when I click a "New Record" button which opens the Partscode popup and allows me to select from the list and after filling in the other fields on the form, clicking a "Commit" button either on a popup dialogue or a button on the form.

I tried using a find script triggered by clicking the PartsCode field but then it wants me to enter a value in every other field on the form also. I need the portal to display all record related to the Partscode from the inventory self-join.

Anyone have a beginners way to do this?

BTY, if any of you wizards out there can help me with a validation problem, this is also something I have to solve. On the Inventory form I mention above. I have a qty field that I enter the qty of parts into an inventory record. This field is validated by a calculation that is supposed to assure that the inventory level of the total of a particular PartCode never goes below 0. This tested value is coming from a related table. My calculation works but only when modifying the record. When I first enter a new inventory record, even if the qty causes the calculated field to go below 0 it still accepts it. When I modify this same value, then the validation catches it. I have tried with Validate on Entry and Validate Always both ways but the result is the same. Any ideas?

Thanks,

RDW