Hi @Halliday, John (FTC),
Have you ever enabled "Allow selections of Groups" for the Person or Group column? Please firstly enable this setting for the column and let me know if it works for you.
If the answer is helpful, please click "Accept Answer" and kindly upvote it. If you have extra questions about this answer, please click "Comment".
Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.