I believe this is a classic case for what QuickBase calls 'Conditional Dropdowns.'
Conditional Dropdowns all you to filter the choices for one dropdown based on the choice in another. In this case, filtering
Companies by
Company Type.
To use this feature, the first step is to make your
Company Type field into its own separate table. Once have done that, you need to relate
Company Type to
Form A. When you have done this, go to the field properties for Related Company and check 'Conditional Dropdown', where 'Related Type' = 'Company: Related Type'.
There is a more detailed guide on the QuickBase Help page here:
http://help.quickbase.com/user-assistance/#conditional_dropdowns.html
