[TYPO3] Workspaces : hide pages in live workspace

[Silithlas]

Hi,

I would like to know... is it possible to setup a workspace so users 
from this workspace cannot see content from live workspace, but only 
content from this workspace?

The goal is, for tt_news, to allow a user to create and edit news and 
then submit them for validation, but once a news has been submitted, I 
would like this news to be hidden for this user in this workspace.

Thanks