I'm having a small engagement party with just immediate family and wedding party (outdoor/social distanced/masks enforced of course) in October provided we can do it safely and the virus has slowed down. Does etiquette dictate that I need to also invite the wedding party's plus-ones? It's held outdoors in a huge open area, with plenty of space to avoid close contact so that's not a huge concern. I'm wondering what's expected when it comes to these kinds of things.