You can filter rank choices the same way you filter select_one or select_multiple choices! In your XLSForm, write a choice_filter for the rank question. This filter should only match options which were selected in the select_multiple question. You can use the selected function for this. It will look something like selected(${your-select-q}, name). name refers to the name column in the choices sheet.
Please see this sample form for a working example.