Hql And sql Queries

I have a Trip and Leg tables. They are related as : One Trip can have 1 or more Legs. And Leg has fields: DepartTime, ArrivalTime, From, To.

I want to Fetch All Trips, and with in each Trip I require only the First Leg (Leg with LeastDeparttime).

How could I write a HQL query for this ?
My Trip Class contains a Set (Collection) of Legs.

some thoughts:
- get the leg and the associated trip instead of the trip and just one leg ?
- use a collection filter ?
http://lizjason.com/blog/2005/11/08/seven-tips-for-hibernate-collection-filters/