Remove specific key from array

My have an event driven site and some of our events are hosted on meetup.com as well. I currently have the attendee list from meetup being merged with the attendee list on my site.

The issue is my RSVP will appear twice since I am on both lists. When the meetup list is being added to my site, I would like to prevent my information from being displayed based on adding that ID to a custom field in my event.

Any help would be greatly appreciated. My code is as follows:

/* load Meetup attendees - code starts here */
	$MEETUP_API_KEY = "b3d07b1b40124b62694a16255445b";		/* UPDATE WITH YOUR MEETUP API KEY */
	$ar_MeetupId = get_post_custom_values("Meetup ID");				// fetch the Meetup ID attribute values
	$meetupId = $ar_MeetupId[0];

if($meetupId!='') {			//	 if a Meetup Id is assigned to the event load attendees from Meetup.com
		$URL = "https://api.meetup.com/2/rsvps?&sign=true&event_id=" . $meetupId . "&key=" . $MEETUP_API_KEY;
		$cURL = curl_init();
		curl_setopt($cURL, CURLOPT_URL, $URL);
		curl_setopt($cURL, CURLOPT_RETURNTRANSFER, 1);
		curl_setopt($cURL, CURLOPT_SSL_VERIFYPEER, 0);
		$json_string = curl_exec($cURL);
		$response = json_decode($json_string, true);
		$count = $response['meta']['total_count'];		// find total count of attendees

		for($i=0;$i<count($response['results']);$i++) {
			$is_attending = $response['results'][$i]['response'];
			if(strtolower($is_attending) == 'yes') {		// only display attendees who have accepted to attend the event

				if($response['results'][$i]['member_photo']['thumb_link']!='')			// if a thumbnail image is available display it in 50x50
					echo '<div style="width:16em; float:left;"><div class="avatar"><div style="float:left; width:5em; height:5em;"><img src="' . $response['results'][$i]['member_photo']['thumb_link'] . '" width="3.75em" height="3.75em" style="width:3.75em;height:3.75em;"></div></div>';
				else
					echo '<div style="width:4em; float:left;"><img src="/nophoto.jpg" width="3.75em" height="3.75em" style="width:3.75em;height:3.75em;"></div>';

				echo '<div style="width:11em; float:left;"><h6>'. $response['results'][$i]['member']['name'] .'</h6></div>';

				echo '<div style="width:2em; float:left;"><h6>(' . ($response['results'][$i]['guests'] + 1) . ')</h6></div>';

				echo '<div style="width:10em; float:left;">&nbsp;</div></div>';

			}
		}
	}
	/* load Meetup attendees - code ends here */