It would be great to have either invisible mode for users or groups, or even restrivite calling.

There are many cases and way to implement some of this functionality.  It would be great if there was a feature to have specific users or members of certain groups that can not be called directly.  They can only be called as a group and normal group calling would take over.  

For example, our IT field team works off tickets and certain calls to the IT group. Since they are all mobile throughout the facility, they wear Vocera badges.  However, users who know their names call them directly.  That circumvents our ticketing system and the normal way to get help.  But if the IT Group members couldn't be called directly that would work great.  However, we would need to have some way to have certain people or groups able to call them directly (managers or supervisors).  Also members of the SAME group can communicate with each other.

We also have some management that refuses to where a Vocera because it makes them too easy to be called and interrupted.  But there are legit cases were certain people really need to be able to find them.  So if they were allowed to call them, but no else was, that would be great.

This would need to be controlled from the admin console, but some limited functionaly might be configurable from the end user through the user console perhaps.

I would envision a tab on the group setup (or user setup) that has a box of groups who can direct call members of the group.  By default it would have Everyone allowed.  But you could remove that and then add which groups are allowed to directly call members of the group.  Something like that.  Perhaps making it so "urgent" calls can great though that setting.

Something along these lines would be great.