friends_get_friends_invite_list( int $user_id, int $group_id )

function friends_get_friends_invite_list( $user_id = 0, $group_id = 0 ) {

	// Default to logged in user id.
	if ( empty( $user_id ) )
		$user_id = bp_loggedin_user_id();

	// Only group admins can invited previously banned users.
	$user_is_admin = (bool) groups_is_user_admin( $user_id, $group_id );

	// Assume no friends.
	$friends = array();

	/**
	 * Filters default arguments for list of friends a user can invite into this group.
	 *
	 * @since BuddyPress 1.5.4
	 *
	 * @param array $value Array of default parameters for invite list.
	 */
	$args = apply_filters( 'bp_friends_pre_get_invite_list', array(
		'user_id'  => $user_id,
		'type'     => 'alphabetical',
		'per_page' => 0
	) );

	// User has friends.
	if ( bp_has_members( $args ) ) {

		/**
		 * Loop through all friends and try to add them to the invitation list.
		 *
		 * Exclude friends that:
		 *     1. are already members of the group
		 *     2. are banned from this group if the current user is also not a
		 *        group admin.
		 */
		while ( bp_members() ) :

			// Load the member.
			bp_the_member();

			// Get the user ID of the friend.
			$friend_user_id = bp_get_member_user_id();

			// Skip friend if already in the group.
			if ( groups_is_user_member( $friend_user_id, $group_id ) )
				continue;

			// Skip friend if not group admin and user banned from group.
			if ( ( false === $user_is_admin ) && groups_is_user_banned( $friend_user_id, $group_id ) )
				continue;

			// Friend is safe, so add it to the array of possible friends.
			$friends[] = array(
				'id'        => $friend_user_id,
				'full_name' => bp_get_member_name()
			);

		endwhile;
	}

	// If no friends, explicitly set to false.
	if ( empty( $friends ) )
		$friends = false;

	/**
	 * Filters the list of potential friends that can be invited to this group.
	 *
	 * @since BuddyPress 1.5.4
	 *
	 * @param array|bool $friends  Array friends available to invite or false for no friends.
	 * @param int        $user_id  ID of the user checked for who they can invite.
	 * @param int        $group_id ID of the group being checked on.
	 */
	return apply_filters( 'bp_friends_get_invite_list', $friends, $user_id, $group_id );
}