LTSpice -Resistor value controlled by on/off Switch
You are running separate simulations with different resistor values, so adding switches is a needless complication. Resistor values can be parameterized and you can simulate with different specific values, simulate while sweeping over a range of values, or use Monte Carlo simulations to simulate many random resistor values simultaneously.

If you use switches you will have to change the voltage sources that control the switches between the simulations...just change the resistor values themselves.