Hi @Yermakhan -
Welcome to the forums!
You can indeed control 4 grippers with a single pin - you would need to splice all 4 yellow signal wires together, and connect them all to battery voltage. Because PWM outputs aren’t typically used on a BlueBoat / ArduRover, you would need to do a bit of setup - this is easier in Cockpit, but possible in QGC as well.
I’m very curious to learn about your goals for such a setup!