Questions about shopping lists

[Jacopo Cappellato]

What is the best way to model a shopping list that is public, i.e it is 
available to all the users (not just the one that created it)?
I've noticed that the ShoppingList.isPublic flag is not used in any 
process. We could use this flag, but I don't think that we should allow 
an ecommerce user to set the flag to Y (the list will then appear in the 
drop down boxes for all the users): it should really be done by a manager.

What is the best way to model a shopping list that is available only to 
a limited set of users?
I could use a special type for the ShoppingList and add custom code to 
show the lists of that type only to qualified users but, again, I don't 
like the idea of letting the ecommerce users select the type of the 
shopping list: we should at least define a way to separate the publicly 
available types from the backend only ones (adding a flag to the 
ShoppingListType? or using a parent type to grop them together?)

I'd love to get your feedback on this because I'd like to provide some 
enhancements (if needed) soon.

Thanks,

Jacopo