IBC 3003.1 - Standby power

I have a unique setup I have come across in the state of Kentucky. 3 MRL's had been installed in a building with 6 floors. All 3 MRL's have rescuevators installed to return the car to a landing and open the doors in the event of a power outage. One elevator in the group is connected to the emergency standby power to go into service powered by the generator. Since all 3 are a group, IBC 3003.1.3 specifies all the elevators need to return to a designated landing then disconnect from the standby power source, and at least one needs to remain operable. Please clarify designated landing. Does that require returning to the main floor of egress? Do battery backups comply as a standby power source? And, since there is no selector switch to transfer the power to either of the other two elevators, are there any exceptions to 3003.1.1 - Manual Transfer requirement?

Are you sure you're seeing "rescuevators" and not brake release devices? A "rescuevator" would automatically cycle the elevators like you suggest, a brake release device is manually operated by a properly trained person to allow the car to drift according to its (im)balance... Bad things can happen if this is not used properly... BAD things... Also note all of the switches must be set properly so the battery is charged and the mainline disconnect should have an auxillary contact so the drift box only operates properly.