You could pulse-width-modulate a 1k resistor with a Cmos CD4066 transmission gate in series with it at a frequency much higher than your circuit. The PWM can be varied from zero where the resistor appears as having an extremely high value, through 50-50 where the resistor is on for half the time and appears as a 2k resistor, to 100% where the resistor appears as its 1k value.
The PWM can be applied to many stages and they will operate exactly the same, without any matching problems.
Since the PWM swutching frequency is very high, it is easy to filter out.
A voltage controlled PWM circuit is an integrator and Schmitt trigger making a triangle wave. Then a comparator is used to give its PWM output when it compares the triangle wave with a DC voltage. :lol: