[SpiralOcean]

You can nest a folder inside of another folder. Not sure if this is what you are asking for.

Maybe you should take one of your most challenging projects and post it up here with all the actions and complexity. Then let users on the forum show you how they would organize it?

There is an art to reducing to complex to the simple... but not too simple because that would break it.

I think action groups are probably what you are going to use within a project.
Example:
Complete Film Booya Baby
-complete preproduction
--get final draft script from screenwriters -waiting context
-complete production
--complete shooting of film
---find genius director of photography
----email bob about suggestions for DP
-complete post production
--find brilliant post house
---call joan about post house suggestions -phone

The method I use for outlining is this:
-write down what you want to accomplish, as if it were in a finished state
-ask yourself: what actions do I need to take to move this to completion
-these actions are child actions. each should have a context
-then go to that first action, ask yourself the same question. can I complete this action? if not, what actions do I need to take to move this to completion? Those actions are then child actions and you have another group.

Keep doing this method for every action until you can't think of anything else.

When you have completed child actions and are left with the action group, ask yourself, is this complete? if not, what actions need to be taken to move it toward completion.

Example:
-complete post production
--find brilliant post house
---call joan about post house suggestions -phone

you called joan and she didn't have any suggestions. So you are left with:
-complete post production
--find brilliant post house

what action can you take to move Find brilliant post house forward?
-complete post production
--find brilliant post house
---search mandy.com for post houses or freelance editors -internet