Design for multi-customer solution

We are working a team on a solution that stores data into mongodb. We want to intorduce a capability of having a mongodb-collection-space (it is my own definition/I am the author of this convention). The collection space is like having different copies of all the collections with different data, like a workspace in eclipse. We need to let the users be working on multiple workspaces each user.
My question is:
How to achieve this goal using mongodb standard features. We are looking to launch just one instance of backend (single server instance) to be connected to multiple versions of mongo data. We want to achieve an easy way to provide a customer login with switch between workspaces, now we have everything - data wise - acting as just one workspace.

Kind regards,