FreeBSD - delete a partially installed gnome2?

I've been trying to compile x11/gnome2 under FreeBSD 10.0-REL, but have been running into all sorts of issues. Eventually I found things indicating that gnome2 is no longer really supported, and that I should use something else (MATE, Xfce, KDE, whatever) instead. But gnome2 installs a trillion other packages, none of which I actually want if I'm not going to be using Gnome. So "make install" of gnome2 has failed, but not before installing a few billion packages that I don't want. I'd like to get rid of them before starting an install of Xfce or whatever. How can I easily delete those that aren't needed by anything that doesn't ultimately go back go the gnome2 package? So, in a perfect world I'd like a command that says: "Figure out all packages that are supposed to be installed via gnome2 (including recursively). For each such package, if it is installed, uninstall it *unless* there is some installed package that needs it and that is *not* among those installed via gnome2 (including recursively)." Is there an easy way to do this? Thanks in advance.