Running two instances of Apache as separate users -- permission denied

I followed these instructions (somewhat) on configuring two instances of Apache -- we have internal apps and third party programs (WordPress, etc) running on same VM so for security and performance reasons I opted for this setup instead of Virtual hosts...

Anyway, I have added a user/group called www-apps to compliment www-data

but unless I set the group/owner of /var/www to www-apps I am getting a "403 Forbidden" error when I access the web site/apps.

Based on the googling i've done it sounds as though Apache needs the base directory to be www-apps (or www-data) but in my case I have to distinct directories under /var/www (ie: applications and websites) each should be owned by www-data and www-apps respectively.

I have done this and I still get a forbidden error. I have disabled all the default apache configurations but I assume that the Apache binary is defaulted to /var/www or something...each Apache instance (ie: apache2 and apaches2-apps) need to bind to the specific directories I just mentioned.

Any ideas? This is a common problem and is certainly a permission issue (as I said above can be solved by making /var/www either www-data or www-apps).

EDIT | I override/provide the docroot via a virtual host but even if I set all directories to owned/group www-apps including and under that -- I still receive the error

Alex