It is possible, but would be extremely complicated. One fan will never appear opaque unless the turbine blades overlap completely (which is possible, though I don't recall ever seeing such a design, since it would be very inefficient). If you have fans spinning in opposite directions, the cooling will be very poor. Fans spinning in the same direction would be a little better, but you'd probably be better off finding a single fan that has overlapping blades as this would almost certainly have a higher efficiency.
Maybe if you described a little more about what you're trying to achieve I could give a little more helpful advice.