I'm really hoping someone with more htaccess knowledge than me can help me out!

.htaccess

######
# Ok I'm hoping someone might be able to help. Here's the final require scenario
# 1. If someone tries to visit either www.domain1.org/ar or www.domain2.org/ar it should take them to www.domain3.org/specificpage
# 2. But only if they're from two certain IP ranges (our internal IP ranges).
# 3. It might only be if it's like 'www.domain1.org/ar'... if the user requests something further like 'www.domain1.org/archie-is-cool' it needs to go that that page.

# Background
# It's on a Wordpress Multisite install hence why there's more than one domain that could be request to the same doc_root
# I'm putting this above the Wordpress htaccess stuff, so that it picks it up before trying to compute Wordpress redirects. 

# Here's what I have at the moment. For some reason it's working for 'domain2' but not for 'domain1' (I'm being sent to a Wordpress page!)

RewriteCond %{REMOTE_ADDR} ^2\.4\.6\.[0-24]$ [OR]
RewriteCond %{REMOTE_ADDR} ^1\.3\.5\.[0-24]$
RewriteCond %{HTTP_HOST} ^(www.domain1.org|www.domain2.org)
RewriteCond %{REQUEST_URI} ^/ar [NC]
RewriteRule ^ https://www.domain3.org/specificpage [R=301,L]

Does it work if you anchor the end of the path regex, for example ^/ar$?

@samstarling No... seems to make no difference.

I converted it down into a 3 liner and it was clearer to understand and now it works.

RewriteCond %{REMOTE_ADDR} ^(2\.4\.6\.[0-24]|100\.15\.6\.[0-24])$
RewriteCond %{HTTP_HOST} ^(www.domain1.org|www.domain2.org) [NC]
RewriteRule ^ar$ https://sub.domain3.org/something-specific [R=302,L]