Forwards, plus-ones and one honest list
Groups are forwarding machines, and for an invitation that is mostly a feature. Someone sends the link to their partner, who sends it to the cousin who always comes. Because all of it is the same single address, every answer from every branch of the forward tree lands on one list, each plus-one counted inside the limit you set rather than smuggled in on a Tuesday voice note.
If the gathering deserves privacy, the page can carry a password and the group alone gets it. When the deadline passes and blanks remain, the app lets you send a reminder to exactly those names on WhatsApp, which is one polite message rather than a personal campaign across three chats.