User Group Limits

How can I further limit User Group access?

Example:
User = AppleMan
Limit him to only view/modify products from manufacturer Apple ('catalog/product/apple')

User = SonyMan
Limit him to only view/modify products from manufacturer Sony ('catalog/product/sony')

This way AppleMan can't delete Sony products and vise/versa.

If this can be done...How about limiting customer views.

Thanks in advance

no neither are supported currently.