Hi Stephanie – thank you for the quick reply. No, I only have one WP install. What I am using, however, is WP Subdomains which allows me to apply an alternative theme to a subdomain. That's why my subdomain page, blog.actusmr.com, looks like it's a separate install. That subdomain is setup as a category in my main domain.
I hope this makes sense. Is there any hard coding you could guide me through to adapt this? Unfortunately I know zero PHP and am fairly CSS ignorant, though I do know HTML.
Thank you! This plug-in is exactly what I was looking for, but I now have this little issue. 
Paul