Data Driven Category On Subsets

[Darius1968]

I'm trying to set up a data driven category to echo the tree structure that I already have in the category pane, but only on a subset that further, restricts the enumeration to only certain branches.  I want this to minimize clutter to a subset of files that I'm interested in right now. 
So far, I have a formula category with about 5,000 files that is based on two nodes of my whole category tree structure, for which a second data driven category is tied to (via Category Formula).  I tried to set this data driven category to type Variable, and have the categories chosen as my variable.  I'm getting nothing at all in my preview.  What am I doing wrong? 

[Mario]

Would it not be simpler to add an extra tab to the Category Panel and restrict that to a part of your hierarchy?
You can add up to 10 tabs.

[Darius1968]

I think you've misunderstood part of my question.  If I were to make use of category tabs, that would allow me to enumerate certain segments of the whole category tree, but it would be independent of the branches that are actually representing my subset of images I'm interested in.  What I want is a way to take a subset of the total images that are in my database, and from this group of images, I want to virtually create a derived category tree that has only those nodes and branches that are relevant to the images I''m interested in. 

[Mario]

I'm not sure if data-driven category are able to do what you want. Or that mirroring sections of your category tree elsewhere will be possible or performant. This was never part of the design. Alias categories would be probably a better way, or formulas.

[Darius1968]

As it stands now, I already have the subset of images I want, consolidated, via a formula category.  I'm just now looking for a way that I can reproduce the tree structure to mirror only those images. 

[Mario]

It would be helpful if you would at least post a screen shot of your category hierarchy, or let us know how you have set up the data-driven category which produces 'nothing'.
There is no category variable you could use for this, because category variables are always for a specific file. There is no variable which returns a list of all categories in your database or something. Which variable did you use how?