Invitation for Pre-Wedding Lunch

I want to throw a "bridesmaid luncheon" for my bridesmaids the day before the wedding, but I also have 2 personal attendants and 4 usherettes that I would like to include as well. I also feel like I should invite my aunts who are going to help decorate the reception space. (All together 20 people). I don't want to call it a Bridesmaid Luncheon since it's no longer just the bridesmaids. How do I convey on my invitations that this is a lunch in honor all of them? Thanks!