No there is not a way to select only the ones to keep, you can only select the ones to clear.
you select all of the seessions that are not associated to the login.
the only other option is to hand code the session destroy. Doing this, you will need to set the login sessions to an application variable, then reset them after clearing, for example:
<?php
// Initialize the session.
// If you are using session_name("something"), don't forget it now!
@session_start();
// save User ID session
$UserID = $_SESSION['UserID']
// Unset all of the session variables.
$_SESSION = array();
// If it's desired to kill the session, also delete the session cookie.
// Note: This will destroy the session, and not just the session data!
if (ini_get("session.use_cookies")) {
$params = session_get_cookie_params();
@setcookie(session_name(), '', time() - 42000,
$params["path"], $params["domain"],
$params["secure"], $params["httponly"]
);
}
// Finally, destroy the session.
@session_destroy();
@session_regenerate_id();
//reset user id session
$_SESSION['UserID'] = $UserID;
?>