It may well be that it loads all the pages into memory so that you can access them instantly as soon as you select a page (provided it has already been broadcast of course). So you may well not have control over what it does with them. A bit similar to computer cache memory.
If it's one of the recent sets that is indeed how it works. Given enough time, it will also load all of the subpages into memory so, for example, if you want page 3 of 6 of the TV schedules, it is instantly available, normally by using the left & right buttons on the remote.
