You can use an event on the finish loading event and scroll that iframe to the bottom. To do that you can check this How to properly scroll IFrame to bottom in javascript.
Basically your final code would look something like this:
$(function() {
iframe.contentWindow.scrollTo( 0, 999999 );
});
Note: After seeing your comment about animation... this solution would add a bit of animation, you cannot get rid of that in the specified conditions. If you have access to both the iframe content and your project content maybe you can find an alternative solution.
A second solution (that respects your request) would be to load the destination page with ajax instead of iframe, parse it, and show in page only what you need (for ajax call you can check http://api.jquery.com/jquery.ajax/, for parsing... that's your part).