Alarms are, I believe, user specific, and there is no user in a mail-in database. A meeting is the only way to send your calendar entry to other people, unless you simply forward the document, saying “Mark this on your calendar!”
You can create a meeting with an alarm setting, and all invitees that accept that meeting ALSO get the alarm unless they turn it off. If you don’t set the alarm, they have to set it individually.
Obviously, you can use a “Meeting” for a lot of things that aren’t really meetings, but this is the only way I can think of that you can “force notification” to other users. And even then, they still have to accept the invitation.