Your comments

This feature is quite important to us.  We may have multiple engineers needing to access a server at a time,  running accounts with different privilege levels. 

Currently we are at risk of a lower tier engineer accessing a session in use with higher privilege levels.   Somebody suggested a halfway feature of a 'do not disturb' sign which may be sensible.

Multiple session support to be honest is what I expected.  Every server has a minimum of 2 separate console sessions,  so why can this not be mapped through control ?