Dont do it, even if you find out how,
its a waste that users will not wait for
click away, next google search response
In class, we were talking about this exact issue. We had to basically analyse a fictional website (in .htm files) and make sure it met basic standards, specs etc. We also wrote what we figured would be good and bad aspects of it.
In this site's case, it had a flash intro before it loaded index.htm. It did this every time we went back to the page from another link on the site. Can you imagine the default ringtone used in the intro going off every few mins? :-/
We all got tired of it and just created a shortcut directly to the index page. Everyone pretty much agreed that was a negative aspect of the site.
So even though it's possible, it's not worth the trouble. I think you're better off going directly to the index page. Not trying to bring you down or anything, but from a consumer standpoint I think it would be better :).