Is it possible to have several book navigation blocks within one site?

Hi,

Is it possible to modify the book module so that specific users can create and modify only their own books as well as its outlines but no one else's book? They will also be able to choose to make their books accessible to users or not. Could someone give me an idea of how to go about doing this please or if there's already a module that can provide this functionality?

I'd also like to know if it is possible to have several book navigation blocks within one site with different access settings. So for example, suppose I have 2 books named Staff handbook and Student handbook. I'd like to create a block navigation for each of these books so that when student users are navigating through the pages of Student handbook, they will not see the navigation for Staff handbook. But staff users may see the navigational link for both books. I notice that access settings are dependent on the book navigation and I can't see how to create a duplicate book navigation block.

(I am using Drupal 6.4 and I've tried this wonderful tutorial on "How to make a duplicate Book module" for Drupal 4.7 and older, found here: http://drupal.org/node/102446, but I can't get past step 3 - I couldn't find the line of code to replace in the module file.)

Thanks,
dantina