It is possible to activate a collaborative mode on Nuxeo Studio, so as to let several people work together on the same project. This page provides some details about this feature.
The collaboration mode comes with a Gold Support contract. You can talk about this feature to your support or sales contact, they can enable it on your project.
On the top left corner of Nuxeo Studio interface, you can see the list of connected users. Note that you can subscribe to as many accounts as you need.