well, it appears that you need bi-directional communication since you want your subscribers to tell something to the publisher. so what you can do is setup a framework where your publisher also subscribes to all subscribers and each subscriber also becomes publisher. that way you can have subscribers send messages back to the publisher regarding whatever (data format requirements for instance). so each subscriber is also a publisher and publisher subscribes to all its subscribers. this may be an overkill if you only need one message sent to the publisher. if this is the case, you can setup a queue where each subscriber will put the message and have publisher consume messages from the queue. in either case, you need to send a message to the publisher which means that somehow you publisher needs to be a subscriber and your subscribers need to be publishers