The Person and Organisation modules are intended to store objects which represent
people and organisations of many different kinds: customers, suppliers, staff, etc.
It is a mistake to create multiple modules and types to represent the different
kinds of people and organisations for two reasons: it breaks the unification
principle in ERP5 and it requires to update so many relation fields everywhere.
Instead, use the role category to achieve the same result. Make also sure that
workflows on Person and Organisation as well as security are designed based on
the role category value(s). With this approach, a Person who used to be a staff
and then becomes a customer can be tracked from the same object. Do not hesitate
to implement 'big' workflows which consist in the union of all possible cases.
It may sound complex or heavy, but it is the only way to achieve the unification
of people and organisations. In the consulting phase, the workflow analysis does
not need obviously to focus on the unified complex workflow but rather on simple
workflows on per use case base (ex. customer validation, supplier validation, etc.).
It is the responsibility of the implementer to find a way to unify all these
workflows in a single workflow. The only exceptions to this rule which we know
are some cases in which one wants to use a kind of buffer module to import
people and organisations before copying them into the real module, or some
cases in which one wants to create a new kind of node (ex. animal).