Can you add grandparent level to page hierarchy in any way?

I am extending the website I have for my physio business part of which is a new free to access patient conditions, self help etc side of the site. I would really like to make this navigable through the drop down menu more as well and interlinking but the limitation of single patent/child is incredible limiting. I would like for instance to have a single page in to start this section labelled for example - patient education area, then dropping down from this the main topic hubs- neck, back, upper limb, procedures etc etc, then from these the actual conditions themselves relevant to each area.

Is there a way to be able to make this happen? thanks