So I have created a drupal multisite install with a shared user database and I would like to store the site the user has signed up on.
I have also created a view of user and I would like to filter them by site. Ideally I would like the view filter to be a dropdown, but it isn't essential.
I am already overriding the user_register_form via the template.php file, would it best to create a new text field for the user then hide and set it to the current domain via the template.php file?