We need to set up single-session system. This need for data security in the system. That only one user can enter your login. If another user tries to log in
as the same user, the system must show the error of log in. We speaked with microsoft support manager about this task. He said, that this task unnable to do by CRM Online side. Implementation
is possible through the SDK. If it's realy possible, please write how we must do it.