Redirect to parent page if child does not exist

Creating redirects as a client has merged many sites into a single site.

How would I set up a rule to redirect to a parent page if the child does not exist – rather than directly to 404.

Eg
Redirect from

example.com/au/location1/staff (Does not exist)

to

example.com/au/location1

(there are a lot of these subpages which no longer exist)