To simplify attatched circuit

Project is to simplify the attached circuit. I need to reduce the number of components required to operate this circuit dramatically. Operational Description: Trigger source alternates between 20vdc - 70vdc and Ground at "Trigger Switch A". There are 8 total switch sources and inputs to the microchip that are all isolated from each other. GPIO pins in the microchip are normally high at "Trigger Input B" until the trigger source switches to ground then the GPIO switches to low. Parameter Requirements: Microchip GPIO pins need to be able to read when the Trigger Switch A switches between 20vdc - 70vdc and Ground. The GPIO analog range at Trigger Input B for a low state is 0-2.49vdc, and high is 2.5-3.3vdc. Open to any ideas on a new circuit design that drastically reduces the amount of components required as well as protects the input source from any malfunctions that could occur within the circuit.