20 April 2009 at 8:22am
ModelAdmin doesn't let you do any publication/staging functionality, so this will be a bit tricky to replicate.
Your best bet is probably the "Dynamic Grouping" recipe: http://doc.silverstripe.com/doku.php?id=recipes:customising-the-hierarchy&s=group%20tree - Its not pretty, but does the job...
We're aware of the problem (running into it on silverstripe.com/blog ourselves), but its not an easy fix.
Please leave your thoughts and patches at the existing discussion for this problem: