From banners to different startpages

Lets say I have three different banners: A, B and C

I have a main site in flash. Here I want to show a different startpage depending on which banner you have clicked.

So if I click banner A I want to got to startpage A
If I click banner B I want to got to startpage B…

Is this possible to do with actionscript or is this javascript related or perhaps php/serverside.

Any ideas?