Let me show only specific wordpress groups (using their sub-groups nested), so for instance:
Primary Category 1
- Sub Category 1.1
- Sub Category 1.2
Primary Category 5
- Sub Category 2.1
- Sub Category 2.2
... I'm able to hardcode it within the sidebar template, but Let me determine if there's any existing wordpress plugin/widget that enables this in order to easily manage category selection/update via admin panel.
You are able to make this happen while using wp-list-categories tag. I am presuming you are personalising your template which emerged?
The function has enough parameters to personalize it since you need.