2 Engines and 2 Gearbox Boat setup

Hello Friends!
My boat setup has two nitro engines and two gearboxes for each engine.
To move forward - first I need to put the gear and after accelerate the engine.
One servo is controlling the engine throttle and the second servo is controlling the gearbox(move forward or backward). So at all there are 4 Servos for 2 engines and 2 gearboxes and 1 Servo for steering.
Do I need a custom firmware for this setup? or I can configure it in software?


I would use an arduino to do this. Since you do not want to use differential steering, you could just read one throttle PWM signal with the arduino and output the signal to all 4 servos. The arduino should make it possible to control the gearbox servos and the throttle servos with the correct timing. To control idling/stopping the engines you could configure a second passthrough output and read it with the arduino, too.

You could also accomplish this via Lua scripting.