Including two taxonomies in a permalink structure

I am trying to get my head around the permalink structures on WordPress sites, and I’m a bit stuck with what I’m trying to achieve:

My current permalink structure: /%category%/%postname%/

I have a custom-post type called ‘city’, and I want to create a structure like below:

mydomain.com/asia/china/beijing

So just to explain this structure:

asia – This is a term under a taxonomy called ‘continent’

china – This is a term under another taxonomy called ‘country’

beijing – This is the actual custom-post type post with title ‘Beijing’

So I basically have two taxonomies (continent and country) linking to my ‘city’ post type. So the way I see it, I need a structure like this:

mydomain.com/(taxonomy-continent)/(taxonomy-country)/(custom-post)

But I cannot seem to figure out how to achieve this with the permalink structure.

Any help would be greatly appreciated!

Thanks