What Hussar said.
Instead of being confused over an example that you yourself coined (post 764) why not be non-conufsed by an actual play example that I have elaborated upon several times in this thread. (I also think my actual rather than imaginary example is what [MENTION=22779]Hussar[/MENTION] had in mind.)
In my GH campaign, there was an ancient Suloise magical tradition (this is consistent both with GH lore and with WoHS lore as established in DL), which operated in current times primarily in the Great Kingdom (which is little described in the GH folio/boxed set, except to the extent that it is full of mad wizards with ancient heritage). These wizards are called Wizards of High Sorcery; they live in Towers of High Sorcery; and they are governed by a wizadly Conclave; one joins this tradition by taking a test. (All WoHS lore.) The tradition is divided into 3 orders - black robe (mostly necromantic/illusion/anti-personnel magic), red robe (especially elemental magic) and white robe (protective magic and the like), whose power is in each case tied to one of the three moons (Luna, Celene and the invisible black moon). (Again, this is all taken from WoHS lore, although the moons have been Greyhawk-ised.)
This is an addition to the GH game. I think the far-and-away easiest way to describe it - which is how I have been describing throughout this thread - is as adding WoHS to my GH game. It doesn't contradict any GH canon. It takes the basic tropes of the WoHS and GH-ises them.
Can players play WoHS in this game? Yes - as I've already posted several times, to the best of my recollection there were 5 WoHS PCs over the course of this campaign (3 black robe, 1 red robe, 1 white robe). Other wizard PCs included a city of GH native trained by a Baklun refugee to be a Baklun firemage; a Baklun witch; and a psionicist from Keoland who ended up being fed by other party members to a demon (long story); and one of the WoHS started out as a non-WoHS wizard trained in a village outside the city of GH, who took the test during the course of the campaign in order to join the WoHS.