No distinction between guests of same name - 2nd guest cannot RSVP

[LiviaButtons]

I appreciate this is probably an edge case. However, I find myself in the situation where I'm having several guests with the same first and last name.

Current behaviour:
When I attempt to RSVP, it seems whoever was encoded in the attendees first is the only person to show. The second attendee by the same name is never revealed, and thus cannot RSVP.

Desired behaviour - admin side: (nice to have)
If I add a 2nd (or 3rd etc.) person with the same name, I get an error message, and am forced to add extra information that distinguishes the two people. The easiest would be the already existing e-mail field (especially since this is something that the attendee would also have access to).

Desired behaviour - client side: (must have)
If somebody tries to RSVP, and their name appears several times in the database, there's instead a message:

Several people with this name were found. Please insert your e-mail address to ensure you RSVP correctly."

• If the e-mail address matches one of the attendees of that name: -> redirect to RSVP
• If there's no match: -> display message "Apologies, your e-mail address does not match. Please contact the organiser for help."