emacs org mode dependent tasks

Is it possible to introduce dependent tasks in emacs org mode? Suppose I have three tasks Development, Test, Deploy which should be done one after another. I scheduled the first one with SCHEDULED: and DEADLINE: and want that the second is scheduled automatically after the first one is finished (e.g. I can specify offset from the first task's deadline and the duration of the second task). Or can it at least warn me that tasks overlap? Also if I move the schedule date of one task then following tasks should be moved accordingly.

From stackoverflow

• Check out org-depend, in the contrib directory of the org-mode distribution.