I know standard practice is that adult children living with their parents should get their own invitation. We have this situation a few times, and I will be following the etiquette and sending two separate invitations.. However, we are inviting one family that is very close to FH and his family. Their 3 kids are 18, 22, and 25 and all live at home. The 25-year-old's boyfriend will also be invited, but the younger two aren't getting plus ones. As much as it seems odd to put 6 names on an invitation, it actually seems equally strange to mail 4 invitations to the same house. What would you do?