To FIFO or NOT to FIFO

Guys,

Using ControlLogix. I am programming an ro water loop delivery system. Our system can pump enough water for 2 stations (solenoids) at a time. There are 8 regular stations and 2 larger stations that need to operate by themselves. The systems needs to be set up, first come first serve. I originally thought of using a FIFO, but someone could turn on their request and change their mind and turn it back off. Not sure how to deal with that or if FIFO is the best way to go?

You have 8 pumps and only 2 can run at a time?
So if station 2 and 6 request water the other stations have to wait their turn? If during this time station 4 request water is it now first in the que? so if station 6 turns off station 4 will now get water?
The attached program is NOT mine and may not work for you. It alternates pumps based on time and demand. You'll have to modify it for 8 stations and probably remove the time stuff.

Sorry, prolly didn't explain well. There is one pump that loops to 8 points of use(solenoids). The pump and piping is sufficient for 2 stations, so I need to limit the rest.

Ok well the program example should still work for it will just be solenoids and not pumps

Thanks Matt, I'll take a look.