Mavproxy broadcast mode

Is it possible to run mavproxy on broadcast mode? so all users on my private network can get the packets on GCS? Right now I manually add the IP of my GCS nodes. I want all the nodes in the private network be able to communicate.
for video broadcast I successfully broadcast the video stream by using ip for transmit. but with mavproxy its not working as expected

As said in here:

A UDP broadcast can be made via the udpbcast:: that starts as UDP broadcast then locks onto the first client that connects. specifies the valid client range. For example, udpbcast: will connect to the first client in the to range on port 14550.

For a workaround, you can start a mavproxy as a screen session and programmatically send output add CONNECTION_STRING to this session.

TCP also allows multiple connections (at least via mavlink-router).

Might I ask how you setup the listening port for the GCS to receive the UDP broadcast? Thanks in advance!