Google Docs Spreadsheet - Better access control needed

I use Google docs to maintain many documentations for a non-profit organization and this has been a very useful, money & time saving application. In my view, following three features will immediately enhance what is already a excellent collaborative product.  These are low-hanging fruits.

• User access control at worksheet level to view
• Copying more than 1000 (one thousand cells) at a time
• Multi-column sorting

In our non-profit organization we have multiple chapters controlling their own documents/ spreadsheets and some times there are situations where I would like to have a single spreadsheet but each work sheet is visible only to a particular chapter or member. For example, a common spreadsheet with 50 worksheets (one for each US state) should appropriately be visible to these chapters.  A California chapter can view California worksheet only and not others.

Currently, I can control the editing access through "Protect Sheet" but not the viewing. See below.