The idea of two pumps is so the well pump can be much smaller for the Geo at lower pressure. Instead of a 1HP pump feeding the Geo and house at high pressure, a 1/2HP pump feeds the Geo and the 1/2HP booster pump only comes on when the house uses water, as the house needs more pressure tan the Geo. You can have as many different pressures coming off the 1HP pump as you like, but it is still going to pull twice the load of a 1/2HP pump.