You should be able to use an intermittent siphon arrangement to get it to be all-or-nothing. If you have adequate flow from the source (i.e. you're not using most of the river and your main penstock is of adequate diameter) it shouldn't suck out and oscillate. (If not you could still arrange enough storage at the valving location so it oscillates with a very long period, making the "a nozzle is running out of water" stage a very small percentage of your operating time.)
The trick is to have the difference in height between the opening of the down-facing end of the tap and the level where the water starts running out (sucking out the bubble) greater than the amount that turning on one tap drops the level in the standpipe. If your hysteresis from the siphon is greater than the pressure drop you don't oscillate. (If it's too large all that happens is you don't start up until the head is higher than it needs to be.)
You should be able to construct all this cheaply by putting down-facing elbows INSIDE the standpipe at each tap. If it oscillates, add progressively longer nipples to increase the hysteresis until it works smoothly.
But rather than trial and error you can figure this out in advance: Measure your pressure difference on your current setup with zero, one, two, three, and four jets on. Convert that to inches of water and make your intermittent siphons a bit longer than that when you build your standpipe. (You can use screw-in nipples so you can change the length if you're not sure this will get it right.)
Note that it's reasonable for all the taps to be ALMOST the same height, spaced much more closely vertically than the start/stop height difference, so you get about the same head no matter how many jets are running.