Activate relays by different voltages
The LM3914 is probably worth considering - it is a linear bargraph driver typically used as a sound level meter. It is able to drive one LED at once or be used in bar-graph mode. The point being that it has a bunch of analogue comparators and gates that virtually do what you want: -



Instead of LEDs you should be able to add a transistor to the outputs you want that can drive a relay (think ULN2003 for instance) such as here - it uses transistors to activate relays.