Let´s suppose that you have a single-direction motor that is controlled by P2 switch (mode 1). In case you need one of the timers to run only when the motor is running, assing P2 driver as a "Switch" in a standard way in the detail of particular timer (moving from position "idle" to full throttle).

In the default setting the timer switches on only at half throttle - this might be modified in Advanced Properties - Sticks/Switches Setup. Here select P2 control and set Switch On and Switch Off consistently  at about -75%. This will move the switching level of the specified timer and the timer starts already at small deflection of a throttle control.