It should be possible. When you make an ADR on My Disney Experience, they ask who will manage the reservation, and you have to pick someone from your party (18+ years of age). So, if you make the Candlelight dinner reservation manager the one person who wants to go, and then set up a second dinner reservation with yourself as the manager for the rest of the group, it should work fine.
Seems like a reasonable thing to be able to do, given how many large groups of people come to Disney, many of whom split up during they day in any given park...