How to enforce a specific sequence of pages access?

[bogdan]

Hi,

I'd like to make sure that users access pages in a specific sequence. For
example, if a site consists of 3 pages, I'd like users to access first
Page1.aspx, then Page2.aspx, and then Page3.aspx. But they should be able
to go back in a 'random access' mode and be able to access Page1 from Page2,
Page2 from Page3, and Page1 from Page3.

What is the best way to enforce it? How do I prevent a user from displaying
Page2 without first visiting Page1 (which has a link to Page2)? For
example, a user can set a bookmark on Page2.aspx and then at a later time
might try to access it directly. How do I force him/her to go to Page1.aspx
instead?

Thanks,
Bogdan