I need to be able to drag groups on the timeline to change start/end dates and have all sub-tasks move with the group.

I can't find a way to do this, have tried the usual combo-key+mouse-drag combinations. Am I missing something, or is this not possible?

If not possible,

(i) should it be?
(ii) what other methods are there for moving groups of tasks? We need to do this in order to use plan to schedule every project in our studio.

andy