Our Agile process is (at a very high level)
Epic = Business Objective. It can contain one or more features and or stories
Features = tangible set of functions that can span more than one sprint. A feature usually contains one or more stories and tasks.
Story = a small set of one or more tasks to complete a function/s that can be completed within a sprint.
Task = a set of actions usually part of a story
Sub-task = subset of actions to partially complete a task
I'm looking for an addon that allows to enable Feature issue type within the hierarchy of issues as Jira (unbelievably) doesn't support this standard agile approach.