Establish a live communication channel exclusively for website members! (using Telegram or a similar method)

[laa]

Good evening... Let me ask directly without taking up too much of your time; 1) Without using our phone number, 2) Preferably without a database, and 3) Preferably by backing up dialogues to the cloud (not mandatory), it is not necessary for members to dialogue with each other. It is sufficient to have only bilateral correspondence and document submission between site administration and members, as well as making announcements to members collectively. What options are available to establish a communication channel exclusively for site members in a practical way? For example, is it possible to integrate widespread applications like Telegram into a website? I would greatly appreciate your contributions, based on your knowledge. Thank you in advance...