i would use a server side scripting and just chuck something in teh url you are sending
if (req.getParameter("a").equals("1)){
show frame here
}else{
show frame there
}
URL: http://location.com?a=1 and http://location.com?a=12
thats java btw
would give you 2 different pages, i could show you the code to do it in php or asp .net as well and the rest of them could show you in the other languages they no.