Preventing history entries being made

Some of my pages are implemented using iFrames and tabbed sections,
which, as the user browses about the page, causes lots of stuff to be
added to the history stack. Is there a way for an iFrame or other page
to prevent itself being an entry in the history stack? As it stands this
renders the back button not very useful.

Some googling tells me I probably can't do this, but you never know.

Thanks,

-- tim