I want to have a multi select drop down menu so the Admin user can choose to show certain individuals on any Page.

page.php getCMSFields code

 // get all existing individuals
          $individuals = DataObject::get('Individual');
		 
		      if (!empty($individualss)) {
		            // create an array('ID'=>'Name')
		         $map = $individuals->toDropdownMap('ID', 'FullName');
		            // create a Checkbox group based on the array
		         $fields->addFieldToTab('Root.IntroPanel',
		              new CheckboxSetField(
		                  $name = "Individuals",
		                   $title = "Select Contacts",
		                 $source = $map
		           ));

I think this needs to be differnt in silverstripe3

$map = $individuals->toDropdownMap('ID', 'FullName');

I was thinking if this isn't posible maybe i could create a shortcode, but a shortcode would not be easier for the admin user.

$map = $individuals->map('ID', 'FullName');

answered my own question