Splitting url by nth characters - .htaccess

Question

I have a site that is getting too much traffic and I want to cache some of the pages, which should alleviate the problem.
I have a system for this in place already, but the issue is the url structure would lead to 11.365 million pages being saved in one directory, e.g.
dir/* <- 11+ million pages saved in this directory.
And this will make things very difficult when it comes to deleting the directory.
Via a predictive search I am using JavaScript to split down the cache like:
people/joh/n-j/one/s.json
Which is more manageable to delete.
Is there anyway I can use mod_rewrite to split urls down in the same way, e.g.
User loads /people/john-jones
Use mod_rewrite to see if caches/html/people/joh/n-j/one/s.html exists, if so server it
Else go to PHP an generate the page
I have a rule for this already, but not with splitting:
RewriteCond %{SCRIPT_FILENAME} ^(.+)\/cache [NC]
RewriteRule .* - [E=PATH:%1]
RewriteCond %{SCRIPT_FILENAME} !-f
RewriteCond %{SCRIPT_FILENAME} !-d
RewriteRule ^.+ %{ENV:PATH}/index.php?request=a&c=search&m=people&p=$0 [L]

Answer 1

Give the following rules a try:
RewriteEngine On
RewriteRule ^(people/.*?)([^/]{3})([^/]+)$ /$1$2/$3 [R=302,L]
RewriteCond %{DOCUMENT_ROOT}/caches/html%{REQUEST_URI}.html -f
RewriteRule ^ %{DOCUMENT_ROOT}/caches/html%{REQUEST_URI}.html [L]
The suggested edit by OP was rejected in peer review. Here's the solution OP went with:
# Set an environmental var for the root directory, so it works on local dev and live servers
RewriteCond %{SCRIPT_FILENAME} ^(.+)\/index.php$ [NC]
RewriteRule .* - [E=PATH:%1]
# Pick up the actual request from query string and set it as an environmental var
RewriteCond %{QUERY_STRING} ^request=names\/(.*?)([^/]{3})([^/]+) [NC]
RewriteRule .* - [E=SN:%1%2/%3]
# If a cache paged exists, internal redirect to that
RewriteCond %{ENV:PATH}/cache/html/names/%{ENV:SN}.html -f
RewriteRule .* cache/html/names/%{ENV:SN}.html [L]
# Send requests that are not cached to php
RewriteCond %{SCRIPT_FILENAME} !-f
RewriteCond %{SCRIPT_FILENAME} !-d
RewriteRule ^.+$ index.php?request=$0 [QSA,L]