The static pressure of the water is not enough information to tell you how many showers can run at the same time. You might need to consider upgrading the water supply if it is ½".
As mentioned, you could consider a bronze pump to circulate hot water from a cylinder to all the rooms and prevent wasting water running taps to get them warm. The hot pipes would need to be well insulated.
As mentioned, you could consider a bronze pump to circulate hot water from a cylinder to all the rooms and prevent wasting water running taps to get them warm. The hot pipes would need to be well insulated.