I don't know if I understood your question really well but...
Isn't the answer to your problem a webservice? You could create a webservice that receives some sort of "password" and if the password is right you return the data JSON/XML formatted.
But you are talking about push, that means that when your server have new information you want to notify your client's server about the new information. I would say that what you should do in that case is make a request to the client server notifying them that you have "new stuff" and then after they have been notified they simply go ahead and use your webservice (mentioned above) and update their data.
I hope this answer your question or gives you and idea of how to do it.