How do we notify users when they are assigned as proxies?

Dear everyone,

When setting another user as proxy/delegate, that person has acccess to your profile for a certain period. How do we set that the user gets a notification in the system about the fact that he or she is assigned as proxy? Because for us the situation currently is that users can be assigned as proxies/delegates, however they don't get the notification in the system about it.

Furthermore, as different employees belong to different legal employers, we would only want users to be able to assign proxies from their own legal employer, so that the legal employers are not overlapping. Do you have any advice on how to limit the chosable users?