you mean connect all four pumps to oone output from the P94?
No. Absolutely not.
The P94 would do the job, being a mixer and two ESCs, but, like I said, the pump motors need the extra bit of control in the power distribution. Often, the pumps dont care which way round the power is connected, they just suck up from the hole underneath and blow out of the nozzle whichever way they rotate. Because of this, each pump needs a diode connected the right way round so that it only switches on when you want it to. If you were just using motors and props, there would be two motors, one for each side, which would push and pull as required. Using pumps, the pair of motors on each side can be regarded as one motor per side, with two sets of windings, one for forward, one for reverse, and the job of the semiconductor is to stop the motor that is not wanted at any particular time from running. (SEMICONDUCTOR, ONLY PASSES CURRENT ONE WAY)
If you look at the P94 notes, it shows two motors, left and right. You have two pairs of motors, left forward+left reverse, and right forward and right reverse.
ESCs sort out the polarity applied to the motors to decide which way they are going to turn. If a motor has a rectifier inserted into its wiring, it will only respond to one polarity. It follows that, if the rectifier is connected the other way round, the motor will only respond to the other polarity.
At any one time each 20A ESC is offering power to just one motor. For forward, 2 ESCs feeding one motor each, for reverse, the same 2 ESCs feeding the other 2 motors, one each.