How do I allow a single page to be loaded with child-URLs?

Not really sure how to word it for the title, but lets say I have a custom page called “Stores”. I need to have “children pages” accessible via URL, but without creating these children pages. A wildcard system would be great, or a regex slug.

Here is what the store page looks like:
example.com/stores/

need to use additional “slugs” or nested pages without throwing a 404:
example.com/stores/alabama/

These child pages must not be manually created though, which wouldn’t make sense anyway because the content is loaded by “Stores” anyway. Alabama is just a variable.

Accomplishing the same thing outside of wordpress might look like this (in htaccess):
cond > /stores/(.*+)/?
rule > stores.php?state=$1