Use the code below to send a separate email notification for each recipient in a given Email Action. Replace 4933, 4924 with your Action ID(s). You can find an Action's ID in the bottom right corner of the Action.

add_filter('frm_send_separate_emails', 'frm_send_separate_emails', 10, 2);
function frm_send_separate_emails( $is_separate, $args ) {
if ( in_array( $args['action']->ID, array( 4933, 4924 ) ) ) {
$is_separate = true;
}
return $is_separate;
}