Hi all (again) :)

I have a form with a grid. The parent part of the form comes from a Products table and the child part in a grid from an Inventory table. I have a combo box that select products from the products table and displays the product's related inventory records in the grid, as well as some additional info on the parent form.
Problem is, I have multiple instances of the same product number in the parent combo box: as many as entries of that product I have in the inventory grid. These tables have a one to many relationship using a common CodeNumber field.
Any solutions?
TIA
Ulises.