Scheduler (plugin)

Sorry Michael, did not see that one...

Yes you can;

Exclusive limit is hardcoded in addslotsform.html §218

        <td align="left">
            <?php
                $exclusivemenu['0'] = get_string('unlimited', 'scheduler');
                for($i = 1 ; $i < 10 ; $i++){
                    $exclusivemenu[(string)$i] = $i;
                }
                choose_from_menu($exclusivemenu, 'exclusivity', $form->exclusivity, '');
            ?>
        </td>

and in oneslotform.html §110

        <?php
            $exclusivemenu['0'] = get_string('unlimited', 'scheduler');
            $knownslots = count($form->appointments);
            if ($knownslots == 0) $knownslots++;           
            for($i = $knownslots ; $i < 10 ; $i++){
                $exclusivemenu[(string)$i] = $i;
            }
            choose_from_menu($exclusivemenu, 'exclusivity', $form->exclusivity, '', 'allowmoreappointments(this);');
            helpbutton('exclusivity', get_string('groupsession', 'scheduler'), 'scheduler');
        ?>

I guess thats all...