I realise I cannot load all six fans on the one output but how could I have aquasuite controlling one and the rest being driven at the same rate?
Depends on the total watt (TW) output of your six fans. If the TW are less than or equal to the rated output of the Aquaero you will be fine. You simply use only one fan's RPM output for sensing and wire the 12 volts fans in parallel. I don't see why you couldn't also use the same rpm sensing wire on two fan headers providing they are all the same fans. This works well if you are using water temps to raise and lower your fan speed. If you just want it programmed to run at a certain percentage of speed that can be done by the software. It is hard to see in the pic, but I wired 3 120mm Papst fans in parallel. The rated wattage of all three fans was still way below the maximum wattage on the Aquaero fan header. Fans don't use as much watts as you might be inclined to believe...