+--------+
                     | Member |
                     +--------+
                       ^
                       |
                       |
+--------------+     +--------+     +-------+     +------------+
| SignupOption | --> | Signup | --> | Event | --> | EventGroup |
+--------------+     +--------+     +-------+     +------------+
  |                                                 ^
  |                                                 |
  v                                                 |
+--------------+                                    |
| EventOption  | -----------------------------------+
+--------------+