sharing notifications in iCal ?

I use iCal on my (desktop) Mac to pencil events for my bosses. I created their calenders myself, and share them using the subscription utility, which works fine. Only, when I set notifications for the events (e.g. notification with sound 2 hrs before the event), they only appear on my Mac, but not on my bosses' Macbooks or devices.

If you have a clue, thanks a lot to share it with me...!