Well, the editor supports up to 28 different categories. That's not enough?
Each race has "Melee", "Campaign", "Special" and "Campaign,Special" - 4 options.
There are 7 races total: "Human", "Orc", "Undead", "Night Elf", "Naga", "Neutral Hostile" and "Neutral Passive" - that's 7 races.
4*7 = 28.
Of course, some of them might already be taken by enemies (I'm mostly looking at neutral hostile), but that still leaves at least 24 categories open.
If you don't want to use 2 of the options (say, "Special" and "Campaign"), you've still got 12 categories left (2 options * 6 races).