I am trying to dive into Views Plugin writing, and I suspect I've hit a deep end. I'm working on a module which builds on OG Vocabularies, with the aim of being able to assign a given group vocabulary to a particular purpose for that group. For example, you could define a "Waterfall" group vocabulary as a project management field for the group, and in a different group, use an "Agile" group vocabulary. As part of my use case, I need to be able to create an Exposed Filter that will make use of whichever group Vocabulary is assigned to the Purpose configured in the View itself. I am having trouble wrapping my head around how to do this. Using the Taxonomy TID filter, you can select a vocabulary and an interface widget. I want to select a Purpose and an interface widget, have it do nothing except as an exposed filter, and then a View displayed in a given group will route it's widget to the configured vocabulary. (Still working out how to describe this functionality.) At this point, I'm defining my handler like so: function og_vocab_purpose_views_data_alter(&$data) { // This handler is dependent on Spaces OG. if (!module_exists('spaces_og')) { return array(); } $data['term_node']['tid_purpose'] = array( 'group' => t('Taxonomy'), 'title' => t('Term ID by Purpose'), 'help' => t('The taxonomy term id, restricted by vocabulary purpose.'), 'filter' => array( 'handler' => 'og_vocab_purpose_handler_filter_term_node_tid', 'hierarchy table' => 'term_hierarchy', 'numeric' => TRUE, 'skip base' => 'term_data', 'allow empty' => TRUE, ), ); } But of course, it then tries to use tid_purpose as an actual field. Can't use "tid" as that's already taken... Any pointers on an approach, documentation, or modules with similar functionality would be greatly appreciated.