Communication with subscribers

 
Hi,
I would have liked to find out if I could come up with a proposal. I am the signal vendor. I understand that I can not see who is a subscriber, but she would welcome a possibility to communicate with them, I understand that the "What's new" section is visible to everyone (and the unassigned). I should be able to write them to everyone, for example when I want to do a poll in which only subscribers can participate.
 
Telegram is good for this.