Each field of field library should be unified semantically. For example, if our
business template has these three fields my_reference, my_code
and my_product_name, add those three fields to the field library.
If multiple portal types (A and B) use a my_reference field and if
they are semantically distinct, add two fields in the field library named
my_A_reference and my_B_reference.
Finally, those two fields should be proxy fields of a generic my_reference.