Open sliding gate half way with 4 ch relay

I have a 4 channel relay connected to electric sliding gate.

Channel 1= open gate channel 2= stop gate channel 3=close gate (all in inching 0.5sec)

Open gate will keep going until a limit switch stops it, same as close.

Set scene that if channel 4 and channel 1 are pressed together then there is a delay of whatever seconds it takes for the gate to open whatever distance you require and then add channel 2 to stop gate