Perhaps an oversimplification: If you can do it in Python, you can probably do it with PsychoPy.
It looks like the software has code for doing python communication on the GitHub page:
import socket
# Initialize socket
socket = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
endPoint = ("127.0.0.1", 1000)
# Send trigger
sendBytes = b"1"
socket.sendto(sendBytes, endPoint)
You could add a trigger sending to your event loop by adding those bits for sending the trigger into your “each frame” in builder.