You can set the maximum number of connections to the Server at the Site level. With multiple Sites, this means that some Sites can allow more users than other Sites.
To restrict the number of user logins
In the Administrator, connect to the server, then click the Server tab.
In the left pane, click the Site you want to configure.
In the right pane, click the Advanced tab.
Select the Max concurrent logins check box, then specify the maximum number of logins you want to allow to a user at any given time. If the box is cleared, the Server does not restrict the number of logins.
Click Apply.