Unfortunately, just that one wizard gets to utilize the spell. This is a woe of contention for many players who often get the "right spell but on the wrong wizard". Case in point, I've gotten the Deer Knight spell on my Storm and Fire wizard but never on my Death, who eventually just crafted it.
Congrats on the getting a spell though! You may find that it is still useful to the wizard who did get it. It goes well especially if you have an amulet of that school because then you can use the spell just like if it was from your own school!
Best of luck farming for the rest of you other wizards :)