Hi,
Based on my understanding of this issue, you want that the users can only edit in the particular spaces, am I right?
So I think we can use Restrict Editing to do that.
Restrict Editing Control what types of changes can be made to the document.
When you select Restrict Editing, you see three options.
- Formatting restrictions This reduces formatting options, preserving a look and feel. Click Settings to select which style are allowed.
- Editing restrictions You control how the file can be edited or you can disable editing. Click Exceptions or More users to control those who can edit.
- Start enforcement Click Yes, Start Enforcing Protection to select password protection or user authentication. You can also click Restrict permission to add or remove editors wholl have restricted permissions.
Quote from:
http://office.microsoft.com/en-in/word-help/protect-your-document-workbook-or-presentation-with-passwords-permission-and-other-restrictions-HA010354324.aspx