[Python] ZeroMQ: How to prioritise sockets in a .poll() method?

Imagine the following code:

import threading, zmq, time

context = zmq.Context()
receivers = []
poller = zmq.Poller()

def thread_fn(number: int):
sender = context.socket(zmq.PUSH)
sender.connect("tcp://localhost:%d" % (6666 + number))
for i in range(10):
sender.send_string("message from thread %d" % number)

for i in range(3):
new_receiver = context.socket(zmq.PULL)
new_receiver.bind("tcp://*:%d" % (6666 + i))
poller.register(new_receiver, zmq.POLLIN)
receivers.append(new_receiver)
threading.Thread(target=lambda: thread_fn(i), daemon=True).start()

while True:
try:
socks = dict(poller.poll())
except KeyboardInterrupt:
break

for i in range(3):
if receivers in socks:
print("%d: process message %s" % (i, receivers.recv_string()))
time.sleep(0.2) # 'process' the data


The threads send some messages without interruption which arrive in some random order at the corresponding PULL-sockets where they get 'processed'.

Note: usually you would connect to one PULL-socket but this example intends to provide more than one receiving socket.

Output is:

0: process message message from thread 0
1: process message message from thread 1
0: process message message from thread 0
1: process message message from thread 1
2: process message message from thread 2
0: process message message from thread 0
1: process message message from thread 1
2: process message message from thread 2
....


Now I want to read from all sockets like in the example but I'd like to prioritise one socket.

I.e.: I want the output to be:

0: process message message from thread 0 <-- socket 0 processed first
0: process message message from thread 0
0: process message message from thread 0
0: process message message from thread 0
0: process message message from thread 0
1: process message message from thread 1
1: process message message from thread 1
2: process message message from thread 2
1: process message message from thread 1
2: process message message from thread 2
....


Of course I can just poll the sockets separately with timeout=0 but I want to be sure ZeroMQ doesn't do this for me already.

So the questions are:

Q1:
Is there another way ( except the built-in .poll( timeout ) )
to make sure I've read messages from one socket first
before waiting for messages on the other sockets?

Q2:
Is there a known best practice to do it manually?

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