Hello,

There's no parent category available currently.
And i'm not sure to implement same system in the future.
But my goal will be to allow multiple category per event or to use a system similar to tag.
In fact, i don't know yet what i will do, but i would like to find something more easy to manage than categories and sub category as Joomla articles do (but as i've said, not yet a clear vision of the best way to manage this).

Today, you can maybe use Features to use them as filters ? (for example, you can use category as main filter, and then use features as filters (no need of use of a image, as feature could be use as a filter in the menu options)).

For info, i will work to have a frontend filtering for features in frontend list, so it could be more flexible than categories.

All depend what you want to do, and how you want to classify your events ?

Regards,
Cyril