[Design] 1-Invitation/Event? or N-Invitations/Event?

[Mimi Yin]

We've been discussion more advanced use cases for Invitations in our 
Stamping and Communications Design Sessions. In particular, we've 
discussed the potential need to have an easy solution for users to 
split off and manage separate Invitation threads for the same Event.

Questions
1. What are the use cases for adding New people to a Sent invitation.
+ New people can see who's already been invited
+ Old people can see new people who have been added
+ Everybody sees the same Event Body (ie. Agenda, Directions to the Event, etc)
+ New people get a custom note
+ Replies from New people are part of the Same Thread as Replies from 
Old people

2. What are the use cases for creating a separate invitation for the 
same Event.
+ New people don't see who's already been invited
+ Old people don't see who's been added
+ New people and Old people sometimes see the same Event Body, 
sometimes see different Event Bodies (ie. Agenda, Directions to the 
Event, etc) What are use cases for each?
+ New people get a custom note
+ Replies from New people are on a Separate Thread from Replies from Old people

Does anyone have any real life examples they can share from the last few weeks?

I think we have a pretty well-defined design for Scenario 1. Scenario 
2, we've talked about and sketched out at a high level, but there are 
a lot of thorny questions to figure out.

1. How do we have UI that accommodates both Scenarios without confusing users?
2. Is 1 scenario more common than another? How is that reflected in the UI?

Mimi