Simulating RF Remote Button Press via Relay

[sebagsm]

Hi everyone,
I'm using a KC868-A16, and I have an RF remote control that operates at 12V using a 12V battery.
My goal is to use the KC868-A16 to simulate a button press on the RF remote, so I can trigger it from Home Assistant.
I’ve opened the remote and soldered two wires to the button I want to control. I know that:

• The button is normally at 12V
  
• Pressing the button pulls it to GND
  

I understand that directly connecting the remote’s 12V logic to the KC868-A16 outputs is not safe, since the remote is powered by its own 12V battery and the GNDs are not shared.
So instead, I want to use one of the mechanical relays on the KC868-A16 (e.g. Relay 1) to physically short the button pins, just like a real button press.
My question is:

• Am I doing this the right way?
  
• where to connect the 2 wires on the KC868?
  
• Do I need to do anything else to ensure safety or reliability?
  

Thanks in advance!