I am not sure how to explain the idea of an engagement ceremony to my extended family. To them, you are engaged as soon as you tell everyone you are. Engagement parties are just to introduce you to people as a couple. You don't typically expect non-local people to travel much to come to them, and you can have as many parties as people are willing to throw for you. Or you could not have any. (You don't throw them yourself.)
But in F's family, the Engagement is more than just a party. There's a ceremony, and before that happens you're not officially engaged. You're just planning on getting married. Maybe you're pre-gaged. Engaged to be engaged. And you don't get more than one engagement. It's just the one, because it wouldn't make any sense to have the ceremony more than once.
So how do I get it across to my out-of-state aunts and uncles that they should come to this shindig, and it's a bigger deal than a few plates of hors d'ouevres and some chitchat?