thanks for these suggestions. But I don’t prefer using IFTTT. I prefer a direct access from ST to the switch.
But I will keep these in mind for other solutions. They seem nice.
for the moment , I opened up my intercom system and found the 2 wires that I need to loop for the door to be opened.
I just need to make the modification to a Sonoff SV as described in the video I posted.
that will be the neat solution I need.