Identical rewrite rules for multiple websites in apache.conf - mod-rewrite

Question

I'm trying to setup multiple websites in Apache.conf to include identical RewriteRules, and avoid having to use .htaccess files in the root dir of each website. The websites are all running the same application, and the .htaccess files are identical. This post gets a bit long so please bear with me.
Applying the rules separately to each directory basically WORKS:
<Directory /var/www/sites/sitename/>
# Rewrite any calls to *.html, *.json, *.xml, *.atom, *.rss, *.rdf or *.txt if a folder matching * exists
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_URI} !public/
RewriteCond %{DOCUMENT_ROOT}/public/$1.$2 !-f
RewriteRule (.+)\.(html|json|xml|atom|rss)$ $1/ [L]
# Add a trailing slash to directories
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{REQUEST_URI} !(\.|\?)
RewriteCond %{REQUEST_URI} !(.*)/$
RewriteRule ([^/]+)$ $1/ [L]
# Rewrite any calls to /render to the image parser
RewriteCond %{REQUEST_URI} render/
RewriteRule ^render/. app/parsers/slir/ [L]
# Rewrite routes to index.php if they are non-existent files/dirs
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^(.*)/$ index.php?/$1/ [L,QSA]
# Rewrite any file calls to the public directory
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{REQUEST_URI} !public/
RewriteRule ^(.+)$ public/$1 [L]
# Allow basic authentication
RewriteRule .* - [E=HTTP_AUTHORIZATION:%{HTTP:Authorization}]
</Directory>
I have 20+ websites that require the same rules, so it seems pretty ineffective having to include the entire block above for each directory. I have tried a few things, and although I feel I'm onto something, they produce wrong results:
<DirectoryMatch /var/www/sites/[^/]+/>
{{ RULES_BE_HERE }}
</DirectoryMatch>
<Directory /var/www/sites/.*/>
RewriteBase /
{{ RULES_BE_HERE }}
</DirectoryMatch>
The best solution I can come up with, is using an Apache include file for each directory like this:
<Directory /var/www/sites/site1/>
Include /etc/apache2/myrules.conf
</Directory>
<Directory /var/www/sites/site2/>
Include /etc/apache2/myrules.conf
</Directory>
<Directory /var/www/sites/site3/>
Include /etc/apache2/myrules.conf
</Directory>
Obviously I don't have too much experience with apache.conf and rewrite rules. Anyone has any sound advice? Any help appreciated.