Titan does not have a way to deal with that natively. You could, however, use EventGraph
which is a graph wrapper over blueprints:
https://github.com/tinkerpop/blueprints/wiki/Event-Implementation
EvenGraph
will pop off events to a listener that you write to gather the events.
EDIT: The above answer applies to TinkerPop 2.x and Titan 0.5.x and earlier. In Titan 1.x and TinkerPop 3.x one would rely on EventStrategy or Titan's Transaction Log.