I would like to maximize the PR on my forum display and thread display pages, without sacrificing PR to less important pages. (for instance, the newthread.php page)

Now suppose there are 5 links on page A. Normally, page A's PR will be spread out to the 5 pages. But now if I added a robots.txt file which blocked indexing of two of the links. Would page A's PR now be spread less thin among 3 pages? Or would it be spread just as thin, but 2 of the pages would be entitled to a share of PR but just wouldn't use it.

I hope this sorta made a bit of sense.