Verifing Supervisor login

Hi,
For Ignition 7.9 , I'm looking for a solution for the following situation :
Operators are logged in using their normal user & password . But some specific actions require special supervisor verification. So i'm looking for a way where if an action (fi button pressed) is triggered, a (supervisor) user & password is requested. This is then checked with the user database to check if this user is indeed member of the supervisor group. If this is the case, we then continue with the action (and if possible log the supervisor that approved the action). If the second user isn't a supervisor, the action is cancelled.
How can I do this 1-action user verification, while at the same time making sure the operator stays logged in for the remainder of his session ?

Thanks

Try system.security.validateUser

This was what i was looking for. I just couldn't find it.
Thanks