filters a Gravity Form to prevent submissions from an already submitted IP, good for spam prevention

limit_submissions_by_ip.php

<?php
/**
 	* limit_submissions_by_ip()
 	* filters a Gravity Form to prevent submissions from an already submitted IP, good for spam prevention
	* change the ID to match your form (ex: gform_pre_render_6)
	* @param $form (array) the form
	* @return $form (array) the filtered form
	* @author Joachim Kudish <[email protected]>
	* @link http://jkudish.com
	*/
add_action('gform_pre_render_1', 'limit_submissions_by_ip');
function limit_submissions_by_ip($form){
    global $wpdb, $current_user;

		$current_ip = $wpdb->escape($_SERVER['REMOTE_ADDR']);
		$table_name = $wpdb->prefix.'rg_lead';
		$sql = $wpdb->prepare("SELECT * FROM {$table_name} WHERE form_id = %d AND ip = %s", $form['id'], $current_ip);
    $last_submission = $wpdb->get_row($sql);

    if($last_submission) :
    ?>

    <style type="text/css">
        #gform_wrapper_<?php echo $form['id']; ?>, .post_content > h1, .post_content > p { display: none; }
    </style>

    <div class="error">
        Our records indicate that you've already submitted a registration from this IP address. </a>
    </div>

    <?php 
		$form = array(); // give it an empty array so that it doesn't generate the form at all [the whole goal is to keep spammers away after all]
    endif;

    return $form; 
}

hi, is there any way i can limit access of site members to seeing form entries base of a field? I have a form and it has a city field, I want defined admins for every city whom can only see entries are from that city