Nesting Cube View Groups or Profiles

You cannot nest CV Groups > other CV Groups nor CV Profiles into other CV Profiles. 

But you can nest multiple CV Groups into a single CV Profile.  A CV profile is just a collection of one (or more) CV Groups.  And you can nest CV Groups into multiple CV profiles by recycling the groups and adding to profiles over and over.

So you could create a Canada Regional Monthly Reports and a US Regional Monthly Reports profiles and nest the various groups into each of those.

Alternatively, you could consider presenting cube views via individual WF profiles by embedding the cube view profile into the 'Cube View Profile Name' Property on a WF.

Lastly, you may be able to use a custom dashboard or Narrative Reporting to create the groups in the manner in which you want to present them to users.  Narrative Reporting is available in the MarketPlace download for Standard Application Reports.  NR will allow you to create groups of reports and display them in a specific way to users.