When in crossfire you can only use the 3 monitors off of the first card and you will need an active display adapter to do so. The second card will add processing power to the first for gaming purposes. In order to use four monitors at once you will have to disable crossfire mode in the catalyst control center.
Sorry, it was badly phrased. I'm not a gamer and use the 4 monitors to keep a number of programs open concurrently for research purposes.
As the second card is on the way, I'm sure that I will have enough options to ensure 4 separate monitors.