Synchronous Zooming

In Microsoft Excel 2003, you can open more than one spreadsheet in the same window, and then if you go to Window/Compare Side by Side with..., you can view more than one spreadsheet at the same time. In fact, if you then choose the "Synchronous scrolling" button, you can have the two spreadsheets display the same window (i.e. if you scroll down in one, the other scrolls down likewise).

My question is: Is there a similar feature available in Autocad (Civil 3d '09) to where you can have more than one drawing open in the same autocad window, and have "Synchronous Zooming and panning", to where when you zoom in or out in one window, the other displays the same window or if you pan in one window, the other shows the same pan.

If anyone knows how to do this, it would save me a lot of time. Thanks for your help, and let me know if my situation is unclear at all.

kc

Is this of any use:

http://www.autodwg.com/dwg-viewer/dwgcompare.htm

Thank you for responding so quickly. That's definitley on the right track, I just need to be able to modify each drawing as well (read and write--not just read) Any other suggestions?

BTW I do know about autocad's feature Window/Tile Vertically, it just doesn't synchronize the zooming and panning.