One way to do this is to create a specialization of the Template entity in Excel Importer. Then you can make some additions to that entity to control visibility. These changes could include adding boolean or enumeration attributes, access constraints via XPath or using both of those things together (for instance, add boolean attributes that indicate what user roles should see the templates and then use those attributes in the XPath of the access rules for the entity. Note that you will need to replace the ExcelImporter.Template entity with your specialization in the places in your app where you want to control visibility.
Hope that helps,