You can use a 2-joystick configuration with 2 Victors, one speed controller for each motor on each side. As pointed out before, the programs capability has nothing to do with the number of motors you would need.
You can just you 2 PWM outputs from your RC rather than the 4 in the default code. Assuming you are using 2 motors (1 on each side with 1 victor each) the default code:
pwm13 = pwm14 = Limit_Mix(2000 + p1_y + p1_x - 127);
pwm15 = pwm16 = Limit_Mix(2000 + p1_y - p1_x + 127);
will change to something like this (where you would connect PWM13 to right motor, and PWM 15 to the left motor):
pwm13 = Limit_Mix(2000 + p1_y);
pwm15 = Limit_Mix(2000 + p2_y);
Hope this helps
