enable scripting.
On the page that you want the dice roll to happen, make a link.
Clikc the link script icon.
Enter:
%DICEVARIABLE := 1D2
IF %DICEVARIABLE = 1 THEN
$DEST := @P2
ELSE
$DEST := @P3
Basically, it rolls a dice and stores it into a variable. It then evaluates whether it was 1 or 2 and takes the course of action. Substiute @P2 with @P4, @P5 or whatever page you want.