There is no way to move pages around - other than to simply re-build them.
But yes, you can have Links take you to any Pages regardless of Chapters. To do so, you you need Advanced Scripting enabled, so it shows you the Page Numbers.
Then in the Link (any Link at all, as the Script will override where it actually points) - you add in the Script box off the Link ( := ):
$DEST := @P100
The above will send the Link Click to Page 100.
Note that if you forget the @ in the code it won't error out, but will give the reader a huge SQL Error when they actually play the game.