Can I use diaphragm accumulators to maintain consistent water pressure?
Normal domestic water diaphragm accumulators (usually bladder accumulators are used) would not be feasible as they are used with a pump that cuts off when max tank pressure is reached. When you say "use them as a water source" please give an idea of estimated capacity needed at what pressure.  Perhaps you should be using a simple raised atmospheric accumulator (water tower) that relies on gravity to supply pressure when your "high pressure water" is not available. 8 to 10 meters height should give enough usable pressure, higher = more pressure.