In an archive page diplay all the posts in hierarchical menu of a taxonomy?

When going to an archive page I want all the posts returned to display in a collapsible dropdown list by a hierarchical taxonomy.

All my posts are related to one taxonomy(A) and some posts are related to taxonomy (b) and (c). So no matter what archive you are in I would like the posts to return like the example below.

So if I’m in an archive of taxonomy (c) instead of an archive looking like this:

– post title
– post title
– post title
– post title

it should look like in a drop down of Taxonomy (A)

Taxonomy Term (Parent)
– – Taxonomy Term (Child)
– – – Post title
Taxonomy Term (Parent)
– – Taxonomy Term (Child)
– – – Post title
– – Taxonomy Term (Child)
– – – Post title
– – – Post title