Actually, having different options pages that use the same field groups can be done. The key is using the “post_id” setting when adding the options page. This defaults to options and ACF constructs the option name "options_{$field_name}". If you use the post ID of “options2” for example then acf will use the option name of "options2_{$field_name}". I don’t think that this is documented or well known.
