Virtualhost Isolation

With an Apache server I had a number of Wordpress sites on it. When one got hacked they all got messed up. I then added this code to Isolate each site and after that if one got messed up the other ones were still good:

In the virtualhost config:
DocumentRoot /home/www/public_html/website.com/www
<Directory /home/www/public_html/website.com/www>
php_admin_value open_basedir "/home/www/website.com/www:/tmp:/home/www/CommonSite/www"
</Directory>

I'm not running an NGINX server as the performance is definitely improved but one of the sites got hacked and it spread to all the other ones. How would I add some isolation between the sites so that if one gets infected it isn't spread throughout them all?

Thank you