Two sync accounts in same directory tree

We are a small company. Currently we are running owncloud for replication across devices for each user and have a separate network drive. The network drive provides a space for common, release files that all users have access to (sales documentation, released source code, etc...). However, users have to be connected to the internet to have access, which isn't great. The goal is to use owncloud to replicate both through two separate accounts. Each user has their own account and there is a 'networkdrive' account that replicates folders and files across multiple users.

I could set up two sync areas with owncloud, one group, one private, but my experience is that then users never know where anything else, you lose time looking for it, etc... It's just not as intuitive. It would be better/more intuitive if there is only one directory tree and each client controls the private vs group replication.

I tried to set up two sync accounts in the same folder of the directory tree and using the selective sync but it seems that owncloud erases anything that isn't selected to sync so this doesn't seem to work.

Can anyone suggest an alternative approach or do I have to have separate directory trees for private and group-shared files?

Thanks in advance