You are allowed to have multiple connections to the same remote machine, and those multiple connections can also have simultaneous control as well. But this depends on some settings within the Client Agent, as well as what rights these users have on the remote machine. The Mini Remote Control program does allow multiple remote connect sessions to the same remote machine, however, by default permission will be required (Accept / Decline) from the first user who connected in order to establish each subsequent remote connect session. If the first user does not respond (i.e. Accept or Decline) the second user's shared session request, then the first user will be disconnected and the second user will be allowed to connect. If the first user Accepts the shared session, then the second user will join in, in a shared session which by default will be in View Only mode.
However, beginning in version 4.1 and above, there was a new feature added within the Client Agent Service on the remote machine called "Allow all Administrators to have control" (see below). If this feature were enabled within the Client Agent Service on the remote machine, then someone connecting with Administrator credentials could establish a shared session without requesting permission from the first user that connected, and also have full control of the mouse & keyboard. Please also keep in mind that this feature only applies to Administrators. Users who supply non-Administrator credentials would still require permission in order to request a shared session, and once connected would be in "View Only" mode.
Also, beginning with version 4.2, an Administrator that is already connected to a remote machine can click on the "Allow all connected user to have control" toolbar button 
. However, only if the initial connection was made by an Administrator, and only if the Administrator remains connected during the session. Once an Administrator clicks on the toolbar button, each Client Agent that is currently attached will be "contacted" (both Administrators & non-Administrators), and also allowed to have control. However, please note that in a large environment, this may take a few seconds before they will be given control. Clicking on the Send / Send Refresh menu option may also help expedite the shared non-Administrative connection to have control.
If the first connected user does not have local Admin rights, then the "Allow all connected user to have control" button will be grayed out. That specific user will still have full use of the keyboard & mouse, but each subsequent connection will be in "View Only" mode. The only exception would be if an Administrator connects and the "Allow all Administrators to have Control" setting was enabled (see above).
Please also keep in mind that the "Allow all Administrators to have control" is a setting within the Client Agent Service on the remote machine, and the "Allow All Connected Users to Have Control" feature is a toolbar button within the Mini Remote Control application itself that will only be enabled if you are the first user connected to this machine and you also connect with Administrator rights.
