Manager access only for one resource of a specific context

Hello!

Finally, I have to give up and ask the question here: Can I restrict the user access in the manager to a specific context and one specific resource or resource group?

I do have following contexts:

* web
* us
* com
* es
* de

Each of this contexts has a Blog resource inside. I want create a user group like "US Blogger" and give the users of this group an access to the Blog resource inside of the us/com context only. When the user logs in as manager, I want him to be able to see only the Blog resource.