Interactive video question

Hi there

I have a question that is bugging me for some time. I am about to create some kind of a video presentation website, where the user will be able to “interact” with the presenter - the presenter asks a question and the user will have some buttons to answer it and depending on what he chose the video branches. I hope you get the point…
I can design and develop that in flash but Im considering some other issues. The idea was to rely on flash media server which as far as I know is not going to be able to support this file format as it is going to be .swf. Is there a way to keep seperate .flv files that are going to be streamed by the server and control them by using a .swf file? The reasing for using that is because Im not really sure what will happen if 100+ users connect to a single .swf file 960x540 around 20min?
And if this is really not the right way to do it I would be glad to hear your opinion of how to solve this problem - create this kind interactive videos?

Thank you!