Anyone know how to create automated task lists for event types?

Are there any apps out there that can generate a series of tasks based on a decision? I have to set activities that need to be done by fixed people at a fixed proximity to an event. The only thing that will change is what kind of event.

E.g. For event type 'Small Event', I always need the following to happen:
- 4 weeks before the event, person X must create something.
- 3 weeks before the event, person Y must do something.
- 2 weeks before the event, person X must do something.

Obviously there will be a more complicated task list, but I'm sure you get the idea. I need to automatically generate the task list based on what type of event it is.

Does anyone know of anything that can help?