hierarchy - Checkboxes that allow you to select parent and children as distinct entities

This is a bit hard to explain but let's say I have this hierarchy for a checkbox list:

->Item A
---->Item 1

---->Item 2
->Item B
---->Item 3
---->Item 4

I need to be able to cover both these cases:

• Select Item A and Item B so that you see a chart with data for Item A and Item B


• Select Item A, Item 2, Item 4, etc. so that you see a chart with data for Item A, Item 2, Item 4, etc.

Currently the way this works is that you can check each checkbox individually and get the desired behavior. However, this breaks how everyone expects checkboxes to work because we don't automatically check all the children when a parent is checked. It also makes it so you have to manually check the children if that's what you want.

So my question is how can I have a checkbox hierarchy that both works as users expect (children are checked when parent is) and still covers the case of the parent functioning as its own separate entity.

I think I'll need some secondary click option? Looking for any ideas.

Thanks in advance.