Radio buttons grouped together

I have two radio choices and i only want the user to be able to select Yes or No.  If I give them the same name, only one displays.  I'm not surprised.  If I give them different names, both can be selected.  It seems like there would be another attribute to group them, however I dont' see anything in the documentation.

https://secure.na1.adobesign.com/public/docs/restapi/v6#!/agreements/updateFormFields

This is occuring using Adobe Sign API v6 in PHP using the following call: PUT /agreements/{agreementId}/formFields

$array[] = array(
"contentType" => "DATA",
"name"=> "credit_card_sameas_1",
'assignee' => $strAgentId,
"inputType"=> "RADIO",
"radioCheckType" => 'radio',
"readOnly"=> false,
"locations"=> array([
"pageNumber"=> $iPageNum,
"top"=> 442,
"left"=> 344,
"width"=> 15,
"height"=> 15
]),
'visible' => true
);

$array[] = array(
"contentType" => "DATA",
"name"=> "credit_card_sameas_2",
'assignee' => $strAgentId,
"inputType"=> "RADIO",
"radioCheckType" => 'radio',
"readOnly"=> false,
"locations"=> array([
"pageNumber"=> $iPageNum,
"top"=> 442,
"left"=> 394,
"width"=> 15,
"height"=> 15
]),
'visible' => true
);