Tableau has a feature called "User Filters" which is well supported and easy to use for enforcing row-level security with browser-based exploration of visualizations on Tableau Server. Please take a moment to read this Knowledge Base article describing User Filters and providing a walk-through example demonstrating how to use this feature: http://kb.tableausoftware.com/articles/knowledgebase/row-level-security-and-user-filters
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Absolutely! Just what I needed. Thanks very much.