document from checkbox

Hi all,
I’m working on small idea for a family tree site for my family.

Since each person is a descendant of 2 others, I have an interesting issue displaying it.
What I want to do is to create 2 TV’s, one for selecting ancestors and the other for selecting descendants if any.

Is there a way to query the db to get all documents under specific doc ID in a way I can select which to create a link to?
I saw it here once but didn’t bookmark the page and can’t find it...any help appreciated.

Here you go: http://wiki.modxcms.com/index.php/API:getDocumentChildren

or in Revolution:

getChildIds ([integer $id = null], [integer $depth = 10]) -- returns an array containing the resource IDs of all children of the resource with the named ID;