Customising SharePoint 2010 enterprise wiki

Requirements:

There are 3 different business context:

1. Work
2. Personal
3. Entertainment

When a user comes into the wiki site, there will be a visual webpart embedded in the form to scope this document to 1 of the above 3 context. So if the user would like to post a Work-related wiki article, he can select an option (dropdown list or radio button etc, but on my POC it's only a textbox :P) and when he click on the sharepoint save & close button

the permission of the article will be restricted based on predefined rules.

Solution (after some thoughts):

1. Event receiver to set permissions
2. Using HttpContext in EventReceiver synchronous events (itemAdding & itemUpdating) to get the value to b
3. Customising the master page to include a VWP (visual webpart) to allow user select "context"