Residents start a community email site but did not invite the board

We have a new board member who is pushing the agenda of a handful of residents. These residents start a community email site to complain about things and discuss what they want to see done. They however did not invite the board to participate nor did they invite all homeowners. Now the new board member is sharing emails from the site the board uses to info members of coming events and members use to inform board members of maintenance issues or problems in their community. This is a private email site between homeowners and board members. Now he is sharing all this info on a different site that allows their little coalition to see all complaints or concerns from all homeowners. Please, help.