How to block incoming chatroom messages?

We are running a application in which each user register itself in a single chatroom and then sends some packet periodically to that chatroom.

There's a single user/listener that is listening to that chatroom and parsing the incoming packets.

Now what is happening is that every other user also get the same packet from other users as all join same chatroom.

We want to remove this thing so that only single user who is listening the room should get the packets and other user should not get the other user packets.

Please help as this is very urgent.