How do I pass control to another .htaccess file for all paths beneath a directory?

Question

My site ww.example.com runs WordPress in its root directory, meaning that any paths are redirected to the WordPress install to be evaluated. I also have an install of DokuWiki under www.example.com/path/to/wiki/, which similarly uses .htaccess to deliver wiki pages at paths like www.example.com/path/to/wiki/wikipage.

The file structure on the server stores all the non-WordPress content in a subdirectory called content, so the Dokuwiki install is actually located in content/path/to/wiki/.

Unfortunately, whilst www.example.com/path/to/wiki/ displays correctly, www.example.com/path/to/wiki/wikipage is clearly passed back to the top-level WordPress .htaccess and returns a 404 error.

What do I need in my .htaccess files to make this set-up work?

Example .htaccess files

Top-level WordPress .htaccess

# Rewrite to content directory
RewriteCond %{DOCUMENT_ROOT}/content/$1 -f [OR]
RewriteCond %{DOCUMENT_ROOT}/content/$1index.php -f [OR]
RewriteCond %{DOCUMENT_ROOT}/content/$1index.html -f
RewriteRule ^(.*)$ /content/$1 [L]

# BEGIN WordPress
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /
RewriteRule ^index\.php$ - [L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /index.php [L]
</IfModule>
# END WordPress

DokuWiki .htaccess

RewriteEngine on

RewriteBase /path/to/wiki

RewriteRule ^_media/(.*)              lib/exe/fetch.php?media=$1  [QSA,L]
RewriteRule ^_detail/(.*)             lib/exe/detail.php?media=$1  [QSA,L]
RewriteRule ^_export/([^/]+)/(.*)     doku.php?do=export_$1&id=$2  [QSA,L]
RewriteRule ^$                        doku.php  [L]
RewriteCond %{REQUEST_FILENAME}       !-f
RewriteCond %{REQUEST_FILENAME}       !-d
RewriteRule (.*)                      doku.php?id=$1  [QSA,L]

Answer 1

I would think that all you need to do is omit the path to wiki and content directories from your .htaccess file in the root and include the path in the first rewriterule.

# BEGIN WordPress
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /

RewriteCond %{DOCUMENT_ROOT}/content/$1 -f [OR]
RewriteCond %{DOCUMENT_ROOT}/content/$1index.php -f [OR]
RewriteCond %{DOCUMENT_ROOT}/content/$1index.html -f
RewriteRule ^(path/to/wiki/.+/?)$ /content/$1 [L]

RewriteRule ^index\.php$ - [L]
RewriteCond %{REQUEST_URI} !^/(path/to/wiki|content)
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /index.php [L]
</IfModule>
# END WordPress