How to control LCD monitor with micro controller?
Use an NPN transistor or small signal N channel MOSFET. The GPIO drives the base/gate (the NPN transistor includes a series resistor with the base). The collector/drain is connected to the resistor side of the switch. Have one sub-circuit like this for each of the switches. 

You could also use an IC chip that has open collector/drain output for buffering the GPIOs to the switch connections.