Hi @SeanHa16 .
Yes, you can create one audience using query string parameters in Adobe Target by using "Query Parameter equals" or "contains" condition. You don’t need separate audiences for each string if the parameter name is the same and only the value changes. For best results, use a URL-based audience rule and keep your CTA links consistent in structure (e.g., ?source=newsletter1, ?source=newsletter2). This way, a single audience with conditions like “Query Parameter ‘source’ contains ‘newsletter’” can cover multiple variations.