There is no solution to excluding non-relatives from a family reunion event that won't leave some offended. Therefore I recommend that you try to accomodate everyone while providing exclusive events for family members only.

1. Send a letter to each close relative thanking all family members and friends of family members for wanting to attend. Mention that there will be a family dinner (or other event) exclusively for closest family members only. Seating is limited.

2. Rent a facility where all attendees including friends can meet in the afternoon for lunch with family members. At the lunch make another announcment thanking all for coming and that their will be a dinner exclusively for closest family members only. Seating is limited. Please check your name on the dining list. Other events would be exclusively for "close relatives only"

3. Family members bringing friends would be charged extra in order to rent a large facility that will accomodate all family members and friends for the noon event.