Extend User Groups with ability to pick more than one content start node

[PeterKvayt]

I want to suggest extending the user group with the ability to pick more than one content start node. Right now we can select several content start nodes for a user, but one for the user group. It makes sense to have only one content start node by user group, but there are some situations when you need to set several content start nodes for one user group, for instance, you create user groups by regions and one region has several start nodes in the content tree: storage, settings, etc. So my users with access to the region should have as many user groups as I have content start nodes. It is inconvenient.