Is there a way to replace the Eclipse JDT code completion list with a multi-level tree?

I know the eclipse code completion widget can be customized to add new sentences and even reorder.

I am wondering if there is a way to replace the current list format (or sibling tree if it is a control tree) with a tree of multiple levels.

So, for example, instead of choosing from a list of methods sorted by name, I'll choose from category, then from subcategory, then from items.

I'm not very familiar with this part of the SDK, but I would like to know if this is possible.

Thanks!