Yes, PTZ Controller software can control multiple PTZ cameras, as long as the protocol of PTZ camera supports. For example, Sony VISCA protocol normally can support a daisy chain of up to seven attached cameras. PTZ Controller can control as many as 255 cameras.
PTZ Controller can control multiple PTZ cameras through a serial port. These PTZ cameras are connected to the same computer serial port. They are each identified by a unique hardware ID (address). You can assign an ID to a PTZ camera by adjusting the ID switch of PTZ camera device or sending a command. Detail please refers to your PTZ camera manual.
PTZ Controller can also control PTZ cameras connected on different serial ports. Multi-instance of PTZ Controller can be run on one computer. Each instance can control a camera connected on a serial port. The instance of PTZ Controller can be run with command line parameters.