You can’t. Create a function that loads that file:
function load_admin_page_file()
{
require 'admin-members.php';
}
Then use that function name as callback argument.
In PHP 5.3 you can use a lambda:
add_menu_page(
'Members',
'Members',
'manage_options',
'members',
function() { require 'admin-members.php'; }
);