Currently, graph axes do not provide a way to render separator lines between category groups. While this is generally not an issue for simple scenarios, it can make charts with nested categories difficult to read.

For example, when a graph displays multiple subcategories under a parent category (such as revenue ranges grouped by quarter), there is no built-in visual indicator showing where one parent category ends and the next begins.

It would be useful to provide support for category separators on graph axes, allowing report authors to visually separate category groups and improve readability when working with hierarchical data.