Feed Me with Related Entries Fields - One to Many Relationship
Why not define the attendees as an array in your JSON? This should allow multiples to be added to your field.
[
    {
        &quot;Meeting Title&quot; : &quot;Project Kickoff&quot;
        &quot;Meeting Attendees&quot; : [&quot;John Doe&quot;, &quot;Jane Smith&quot;, &quot;Jim Brown&quot;]
    }
]