+-------------------+
     |    MemberEvent    | --------------------------+
     +-------------------+                           |
       |                                             |
  +----+                                             |
  |                                                  v
  |  +-------------------+     +-------------+     +------------------------+     +------------------+
  |  | MemberEventOption | --> | EventOption | --> |         Event          | --> |    EventGroup    |
  |  +-------------------+     +-------------+     +------------------------+     +------------------+
  |    |                                                                            ^
  |    +-------------------------+                                                  |
  |                              v                                                  |
  |  +-------------------+     +-------------+     +------------------------+     +------------------+
  |  |    MemberRole     | --> |             | <-- | MemberEventGroupOption | --> | EventGroupOption |
  |  +-------------------+     |             |     +------------------------+     +------------------+
  |    |                       |             |
  |    |                       |   Member    |
  |    v                       |             |
  |  +-------------------+     |             |     +------------------------+
  |  |       Role        |     |             | <-- |       MemberJoin       |
  |  +-------------------+     +-------------+     +------------------------+
  |                              ^
  +------------------------------+