Welcome. The residents of the house, there is an urgent need to organize themselves, as their home is threatened by demolition, which they do not want. There needs to be a tool of self-organization through the Internet. It should be as easy as possible for people with low level of computer literacy.
You want something like forum\mailing list with the ability to store the entire history of correspondence and access it through the web. Almost certain that it was in Russian.
Google groups is not suitable, because they have the old bug, because of which the web interface incorrectly displays the letter with encoding other than UTF-8.