Block Signup should add the contact to a list even when they are already on a different list under the same account

I have a use case where we have multiple contact lists under our one account. The problem is that if a user has subscribed to a list in the past it will not add them to the new list instead it says email address is already subscribed.

What should happen is when the form is submitted it should check if the user is on the specific list that they selected (or the default list if the list options are not selected). If they aren't it should do a update_contact() and add the contact to the list.

Here is my first version starting on line 1148

Replace this existing code:

	if($contact):
		form_set_error('cc_email_'.$delta, t('Your email address is already subscribed'));
	else:

With this code:

    if($contact):
          foreach ($lists as $list):
	       $existing_contacts = $cc->get_list_members($list, $action = 'members');
			foreach ($existing_contacts as $existing_contact):
				if (array_search($contact['id'], $existing_contact)):
					form_set_error('cc_email_'.$delta, t('Your email address is already subscribed'));
				else:
					$updated_contact = $cc->update_contact($contact['id'], $user_email, $list);
				endif;
					
			endforeach;
		endforeach;
    else:

I slapped this together quickly in hopes that someone may be able to help me make this work for large contact lists. The problem is that the code above loops through every contact in the list. Any ideas on improving this?

Thanks!