have a look at this thread on Mac Rumors:
http://forums.macrumors.com/showthread.php?t=937722
Seems you need to export the file in Pages on your iPad first.
Also it seems that there is some shareware for the Mac that you can use to automate this ...
As for more than one person using your iMac. Make users for each member of the family. The user management in OS X works nicely. Then whenever the computer is free you can use your login to sync with your iPad. The other members of the family won't have access to your files (unless they know your password)