Trying to understand "updating orbit2 makes 79 packages unintallable ..."

[Joe Buck <jbuck@welsh-buck.org>]

I'm trying to figure out the reason why orbit2 is blocked from testing,
see

http://bjorn.haxx.se/debian/testing.pl?package=orbit2

I understand the problem in principle: there is/are some package/s that
needs the older version of orbit2, and the other "uninstallable"
packages depend on these.  Ideally, though, there should be a way
to figure out some minimal set of packages that is causing the
conflict, rather than displaying a set of 79 and a set of 50.

Is there any way to figure things like this out?  And is there any
way to fix Bjorn's script to show such problems more clearly?

Joe