Arclivin,
Most of the people on this site can write a PLC program to control 4 pumps - and can do it with no timers. However, the first thing you need to do is define what you are trying to accomplish.
Are you trying to maintain a level in a tank?
Are you trying to maintain a constant flow?
Is there another parameter that you are trying to control?
Are you trying to achieve uniform wear?
Are all the pumps identical in terms of key parameters (flow rate, hp, electrical, etc.).
Are they are pumping into/out of the same destination/source?
Is there a maximum time you want to run a pump?
Are there other criteria?
Unless you can define the key parameters, there is no point in writing a program.