^
Ad A gets all red haired traffic
Ad B gets all other hair color traffic
The thing w/ edit target criteria targeting is that you NEED 1 default creative that has NO targeting in it. But as long as all your bases are covered, the default creative should receive no impressions since the ads w/ edit target criteria targeting gets priority for impression delivery over the default creative.
So in your example, if you had ads that covered all possible options under hair color, the default creative would receive 0 impressions.
Okay, let's say I want Ad B to receive all hair colors, I just need to create a default creative for the system that will get 0 impressions, then for Ad B, I will select ALL hair colors, so now....
Ad A gets all red haired traffic
Ad B gets ALL hair colors (including red)
This works right?